Hi Bo,
keep in mind that Premiere is an editing tool and Fusion is a compositing tool.
Fusion is more tailored to give you an huge ammount of control on joining several elements together in a relatively short scene. Premiere, on the other hand, is focused on fastly putting several scenes in sequence.
In other words they're not a substitute of each other.
That said, Fusion operation is very peculiar given its node based interface.
I strongly recomend vewing this tutorials that are focused on the very basics of Fusion:
https://www.youtube.com/playlist?list=PL-T1aXBnhDkLTWRDwWPrVMI21P1QsFCxnhttp://tale2tell.com/fusion-tutorials/Oh and welcome to Fusion!