I know you can go into the enemy territory once you reach level 50.

But im curious. How would you even get into the enemy territory? And what things could I do in there?

Will I be attacked by guards, be able to wander into enemy towns if say im a roleplayer with my buddies?

I know Cyrodill is the only place that has world pvp and im personally okay with that. But I would like to see and many others see some world pvp like a pvp on and off toggle thing even if im in a enemy continent.

So can someone please explain what exactly im allowed to do in the enemy faction and how I get there?

The only thing you will see in enemy territory at level 50+ is appropriate level content and other 50+ players of your faction. You will not see any lower level players.

no you won't be able to gank lowbies in the pve zones.