Hey, so I'm going to try and explain how cyridiil works as best as I can (seeing as I'm sort of new myself) - So you are stuck on what to do? well to be honest even though it might look confusing on the map its actually very simple. The objective is to take over the enemy castle and resource areas outside them.

If you are wondering where all the big battles are at then look at the castle symbol on the map. If theres an explosion looking thing covering the outside of the castle symbol then that tells you that theres a big battle happening at the location.

I take it you are not passed veteran rank yet? if thats the case then do not think you are useless. you can help with the siege equipment and help your team breach the enemy castle (thats what I did at first)

You mentioned the main base? as in the one you started in? if so then that is where you can do a bunch of things - really, this place is where you get ready before going out into cyridiil. In the home base you can buy potions, siege equipment and armor that you can buy with alliance points.

Really cyridiil is just like a giant game of domination. take as many castles and resource points as you can. One thing to note is that to do both of those you need to be with other people since you will face resistance when trying to take over castles and resourse points.

Oh an I almost forgot! the scroll. I'm not 100% clued up on these but heres what I know:

they can be found in other factions (teams) castles and (I think) if you manage to capture them you get extra points and perks.

I hope I sort of helped you out

and I'm sorry for the wall of text aha