I would like to start coyote trapping and would like to know what the best foothold and the best way to set it.

Everyone will have a different answer. You will have to find your best.
Lot of traps on the market that are good traps. From there it's a matter of your personal likes and dislikes and conditions you trap in.
If I had to chose only one set for all situations (weather not a factor) it would be my version of a double dirt hole, a step down dirt hole a close second. The step down dirt hole needs no natural backing ( I don't like creating backing) and is resistant to dug traps , deer, cattle and has great guiding. That's it's advantages. Every set has its advantages and disadvantages. The part of learning
Weather and ground conditions play a big part in what is the best set

Rattrapper - self taught because I wanted to do it at my place for the small and big game management. Check out YouTube and see who you like watching. It’s not as hard as I thought it would be, but I’m also blessed / cursed that I have a pretty high concentration in the area.

Practice bedding whatever trap you go with to get it SOLID and set on sign taking advantage of the predominant wind. In my opinion, that is 99% of it.

These grizzled vets have forgotten more than I’ll learn, but you’ll get what you put into it if you are willing to put in the work and research.

You asked a specific question, so I’ll give you my opinion. What Yes sir said and I’ll add that I use MB-550s.

The best foothold is the max width your state allows. If it’s 5” buy 5” traps. If it’s 7” buy 7” traps. Generally the more expensive the traps the more or better chance you won’t have to do much of anything to them but degrease and set. Some even come ready to set.

You need number 2 size or equivalent.

Yes Sir nailed it. You can watch all the videos and have a pretty good idea of where to start and what to do. Getting out and doing it and failing will teach even more. Pay attention to your failures and you will be well on your way to success. Good Luck

For example I trapped a 6 mile stretch of easily accessible mountain road with about 15 traps. There was no sign, I mean none. But it looked so good and plenty of food running around. 3 weeks not a thing. I set on a mound on the hill above my house. I thought it was a badger mound, and maybe it was, but two days later I had a kit fox. If there's no tracks, there's no game. Rain, snow, freeze all influence where you set, how you set, use wax dirt, switch to snares. The amount of trafficking I would do created paths, and I'm concerned that may be shying animals away. Pan tension to keep non targets out of the trap.

Start with checking with your state laws. Next, go to OSTA ...Ohio State Trapping Association and find when the convention will be and if its close attend great organization with many top notch trappers. Join the assoc. if possible, as they have many workshops and get togethers to share info. Money is tight and like others have said spend your money on quality traps that work for you. Hope this helps.
PM me or others if you have any other questions.

Quality over price on traps. Meaning fewer traps but better quality.

And fewer good sets are better than lots of bad ones.