Need more information to troubleshoot the issue.
At this moment, you can choose FunC and Tact as the programming languages in TVM (TON Network Virtual Machine).
For FunC, here is an overview tutorial you should check out:
On the other hand, Tact has an easier syntax to learn compared with FunC (*FunC is more like a C-like language).
Although you can code in Fift, this is not the case we are talking about today.