I updated the game with a tutorial that should help, but if it doesn't, here's a rundown:
Moving is how you interact 90% of the time. Wanna talk to a character? just move into them. Push a box? Move into it. Ring a bell, move into it.
I also uploaded some gifs to the desc that explain this.
the sole exception to these controls is when you want to give a character an item. Simply face the character, select the item, and press Z. So if i wanted to give Frankie the Fish my Tissue, i would select the tissue, look at frankie, and press Z.
I am currently trying to develop a much more intuitive system than this, but let me know if this helps!
oh also 'undo' is X