content patch

Hello everyone, I am currently working on my first content patch (with Content Patcher), which adds some fishes to the game. I have been looking for a way of setting the fishing location of these fishes to specific floors of the mine (let's say, level 20, level 60 and level 100 of the mines)...

I am new to Stardew Valley modding, and for my first time doing it, I decided to try and edit the look of the GUI. However, I can't find a few of the sprites (no idea what they look like in the spaghetti that is the files). I managed to find and edit the top right interface just fine, but I...