Can anyone show me bottom edge examples like what to look for in understand setting on the bottom up against a sheer wall but what sets one spot a part from the rest? Pictures would be great if possible

When there's a point that that sticks out from the wall or where it's undercut is where you have better luck.if there's food down there for a mink, id still set the straight wall if that's all there is,

Get the Ken Smythe/Bob Noonan book on it, it's really worth the read.

when trapping mink you want to hug verticle structure it can be as productive on land as it is in the water if you know what to look for where it really shines is when you have established ice
when you understand how they hunt and what time of year there after either mice or stageing white suckers in a creek it can be amazing to study the bottom of a creek and see a prominate run bumping the edge
of verticle stucture under the water that you would have never thought to look there before if you really want to understand the set pickup the book by Kenny Smythe called the bottom edge its a good read
and will answer any questions about the set that you might have
take care

I always leaned a large flat rock against the conibear giving the mink a tunnel of sorts to aim for. I would also set up the corners, and middle on both sides.