First off. Do I get to bring stuff with me? Like say the entire printed off contents of wikipedia.
also, I would like find one or two things that hadn't quite been invented yet and 'invent' it.
also, Also, with a modicum of military power, I'd probably start a religion.
This assumes I have time to learn the local dialect
Wikipedia is for my benefit, so I can just read it.
Nobody else needs to even know I have it, necessarily.
Them not being able to read it might even be a boon.
The goal is to get a leg up on things, not start having nuclear reactors in the medieval era.
For example muskets had an iterative development as small incremental changes took place. Relatively small changes made modest improvements.
It would also be nice to know when eclipses are about to happen, for, ah, reasons.