Hi Alissa Moo,
Judging by the dry leaf of red oak that I can see in the background, you must be from a temperate place in the US.
Zelkova (with a "K") is a tree that can forgive many mistakes.
It can grow quite fast when planted in the ground, but stays very small when potted, so I would put it in a shallower container so the root will spread more horizontally, and feed it a lot. Also, it backbuds profusely when pruned.
For instance, I bought a Zelkova sinica last year, almost the same as Zelkova serrata, except for the bark. It was in a deep square plastic pot, and I almost lost it last summer. I repotted it with a much better soil, and in a wider and shallower plastic pot. It's throwhn new shoots the length of last year's seedling:
View attachment 196482
In the top-right of the photo, you can see the base of a crab-apple from seed. Same procedure: I use "spiraling wires to make sure the roots are not disturbed by the wind. Not very elegant, but efficient, and they don't harm the roots of trees that are still in their first stage.