help please this is first time making server i have no clue what im doing

ive attempted this with all versions of mantle ant tconstruct for 1.16.5
forge is 1.16.5

First off, why are you reporting this to Mantle? That is a Tinkers' Construct error as you clearly knew from the fact you mentioned Tinkers' Construct in the report.

Second, this issue would be fixed if you just downloaded the latest Tinkers' Construct version.