I just bought this brush cherry from a local nursery. I repotted it 2 days ago with a basic bonsai soil and some basic bonsail fertilizer pellets since the soil it was in retained waaaay too much water and was definitely going to drown it. I like in nebraska and it gets hot and muggy so I leave it outside during the day in partial shade (2 hours of direct sun, 5-6 hours of shade) then bring it in during the night. I have been watering it whenever I notice the top inch or so of soil is dry. I guess I am just looking for any advice, should I trim it, more or less sun, watering, anything would help. Thanks!!

Post a picture for more advice.
Without seeing the tree, let it grow and regain health. You can prune and wire later. Leave it outside at night as well. The tree can handle it just fine. It's late to be repotting, but what's done is done. If you did any root pruning, hold off on fertilizer for a few weeks. Additionally, keep protected from strong sun for the first two or three weeks.

Here's a picture.

I do not know the species. In general, plants dislike a chake in position. Do not move the plant inside and outside every day. Make up your mind, give it a place and leav it there for the season.

en.wikipedia.org/wiki/Syzygium_smithii
www.google.com.au/?client=firefox-b#q=li...lly+bonsai&gfe_rd=cr

Your Tree looks healthy.
They are quite hardy, love water,fertiliser and good draining soil medium.
Pruning in Spring and Summer no problem, repotting in warm weather is best.
Watch for overcrowding from Too many new shoots/branches and also sap sucking pest like black scale.