The notched leaf ends are typical of Fukien tea aka Carmona.
I take it that is a picture of when you first bought your little tree and were bringing it home? If so, if you can, I would just take it back to where you got it. It already looks in very bad shape. Not only does it have hardly any leaves, but the bark is peeling in several places, which should not be happening. Even if that is a current picture (why take it in the car then?), if you've only had it a couple weeks, it is hard to know what you could have done to a healthy tree to get it to that condition in two weeks and I'm guessing it already had problems when you bought it.
So you made several mistakes to start with: buying a tree before you had any idea what you were buying or what care it needed and buying an unlabeled and probably sick bonsai tree from Wal-Mart. If you decide you really want to get in to the hobby and art of bonsai, buy a tree from a reputable dealer. Or buy a regular tree or shrub anywhere and learn how to cut it down into a bonsai yourself.
If you are going to see if your little tree can be saved, start by taking all the moss and rocks off the surface. Interferes with being able to tell what is going on with your soil and when it needs to be watered.
Do some reading, starting with:
https://www.helpfulgardener.com/forum/vi ... =36&t=1479 general bonsai tips.
Check out the Bonsai Forum here, especially the Learning Library:
https://www.helpfulgardener.com/forum/viewforum.php?f=36
then check out all the good bonsai info in the non-forum part of Helpful Gardener:
https://www.helpfulgardener.com/bonsai/
Our bonsai learning forum here:
https://www.helpfulgardener.com/forum/viewforum.php?f=36
has a thread listed near the bottom of the page on lots of people's suggestions of good bonsai books to get started with
Best Wishes. Keep us posted on how your little tree does!
