1. wearing steel toes boots...
2. stiching it up with some fisning twine and a fishinghook
3. tournaquite untill i can cauterize it
I beleive in all these injuries if they are self inflected on any one person... lets just let Darwin's law work itself out... because the first two seem extremely silly injuries and the one suffering said injury ought to just be ejected from the gene pool... no offense.
We can assume that we do not have access to a hospital, doctors, nurses, and EMT/Paramedics
But... Crushing your foot... depends on which bones are broken and the severity of the injury, The best course would be to splint/immobilize the foot as best as you can, apply a mixture of heat and cold (to promote healing and decrease swelling), any broken skin should be kept as clean as possible, Irrigating with CLEAN water (preferably by means of boiling, chlorine, or condensation) and applying TAO frequently, then covering with a clean (sterile if you can find em) dressing (Gauze, boiled rags, etc)
Finger... From the description it sounds like a nasty cut, (I'm imagining the cut part of the finger is still attached to the body) secure the injured part to the rest of the finger, first cleaning with clean/sterile (again boiled, chlorine, or condensation) , secure with steri-strips (can be looted from any drug store, or anywhere else that sells first aid supplies) or a tefla gauze and tape (again, could probably find at the same place as the steri-strips, look for 'non adherent gauze'), keep clean by irrigation and application of TAO... high risk for infection, so keep it as clean as possible, loot yourself some vinal, latex, or nitrile gloves... you should carry these anyway... ya know, zombie gore and whatnot)
The last one, firstly, bitten by a zombie, your not likely to survive regardless of amputation, and it would require alot of heat to carturize the wound to stop the arterial bleed... I would suggest either finding or making peace with whatever God or gods you may beleive in (or at very least with your own mortality)
Be sure to know what your drug allergies are... find some antiboitics ( names ending in -cillin, -mycin, -azole, -cycline, -floxin... beginning in sulfa- will be your antibiotics (typically)) of course if your allergic to penicillin then stay from the -cillins', Tetracyclines the -cycline's, Sulfa... -sulfa... you get the picture.
Also, for wound healing, multivitamins/ vitamin supplements with high zinc levels rock as far as long term wound healing goes. And if possible, extra protein can help with healing... not over night, of course, but it'll help
Ive been a paramedic for 3 yrs, and I can tell you the medical problems your propose are harsh to throw at someone. So good job.
1. Check the foot for any decrepitis(broken shifting bones). If there are none wrap the foot immediately to prevent any major swelling. Ice, and elevation will help it from getting worse. If you have some drugs with you Ibuprophen, or another type of anti-inflammatory would be great. NSAID's(None Steriodal Anti-inflammatory) are good, but a glucocorticoid would be better. A antibiotic like pennicilin would be good too. If the bones are broken its going to need to be set as best as possible. Start by putting some traction on the toes to align the bones as best possible. Use a compressive wrap to keep them in position. If your close to an abandoned hardware store look for some plaster, or tubes of caulking. Thoroughly cover some ace bandages with mixed plaster, or caulking. Make sure you still have distal pulses distal to the compression wrap to ensure adaquate blood flow to the foot. Apply the ace wrap and allow to dry like a cast. Allow 6-8 weeks of light duty to allow for adaquate healing of bones.
2. It sounds like this is a pretty bad cut. If its just slice you can probably get away with wrapping the finger, and webbing. Cleaning it often with saline to irrigate, and an antibiotic would be ok. If its a nasty slice....Well your going to need stitches to close the wound. Hopefully you have a sutchering kit you've found in a demo'd hospital, if not a fishing hook would work with some sterilized thread. Any type of ligour will work to sterlize, but look for something with higher proof if your going to have to use drinking alcohol. Im not going to try to explain stitches. Its sort of a pain in the ass, get some pig skin from the butchers and practice. There are tons of videos online.
3. Fortunately your body will help you when it comes to the amputated limb. Your veins, and arteries are stretched lightely through your extremities. So they will retract into your arm when cut, and block off some of the blood flow. You absolutely need to make a touriquet though. Its going to also help with the spread of the virus. A tshirt with a stick tucked into the ends and wrapped tight will suffice, you can then tuck one of the ends under your arm pit to hold it in place while you work. I suggest using the fastest way possible to amputate your arm. If you have a saw of some sort use it. It would be even better if is powered. The longer you work on it your going end up going into shock at some point. Maybe not hypovalemic shock, but just system shock from the pain. Your going to want to start an iv on yourself too. If you haven't come across a hospital and lifted iv caths, tubing, line, and bags. You can use a water bottle and acouple of marinating needles. If your desperate and really hardcore a ball needle will work in a pinch too, but your going to have to file a point on it. Mix some salt into the bottled water. Your going to want heat the water up so that the salt will dissolve into the water. Your going to want to use a vein in your foot, because your going to need to be able to use your other arm, and putting it higher in the amputated arm is just going to make bleeding faster. When cauterizing the veins, arteries, and tissue you can use acouple of techiniques. Obviously a clean piece of steel in a nice fire will work really well. If you want to be all hardcore and Ramboesque gun powder will definitely do the trick, but your going to need to treat the burns afterwards. I would try to find some quick clot when your scavaging in hospitals, or ambulances. I know a lot of the units here carry military grade quick clot, and Ive seen what it will do on arterial bleeds. Good stuff, be advised though that its going to burn exactly like hot steel. Best of luck with one arm.