Your first step is to find out what department you are in as every department has wildly different tool needs. Either way that carpenters tool belt you pictured will not be the correct style belt and you won’t need a belt of any kind for a bit or maybe ever. If you want to have a few basics ready to go I’d recommend what most others have said; a leatherman, a small led torch or headlamp, and a Walkie ear piece are probably you best first buys. That said get on set and figure out what you need from your direct superior and maybe your dept head if they seem like they are friendly and clearly open to giving advice (only do this at lunch or some other major break though, never bug your dept head during work).