Remember that everyone didn't know what they were doing at one point, and most people are just pretending they do know what they're doing.

You're obviously competent to have gotten the job in the first place.

In order to learn you have to admit what you don't know and ask for help. Even if it's something that seems silly, someone else will have asked how to do it before you, you're not the first person to not know or to make that mistake.