im new to night fall, i have a question about leaving

how do i get to the main continent with ascalon on it (main game for prophecies) i am totally lost about how i leave the nightfall world... hopefully this makes sense

There's a quest that you take to travel to other campaigns.

For Prophecies: talk to Deras Tenderlin in Kamadan, and take the Terror in Tyria quest.

Alternatively, if it's not open to you yet and you really want over, get a ferry to the Consulate Docks, and from there get someone to ferry you to Lion's Arch.

you must have bought proph, if u have follow the above

You must have Prophecies linked to your Nightfall campaign. Prophecies' world is called Tyria, while Nightfall's is called Elona. If you want to transfer between two continents you must progress in the Nightfall storyline until the quest 'The Time is Nigh'. After this, accept the quest 'Terror in Tyria' from Deras Tenderlin in Kamadan. Now, just go to the Consulate Docks which you have unlocked by doing the quest 'The Time is Nigh', and just get on with the quest. There's no fighting in it, only a bit of talking and a cutscene. Then your character will be in Lion's Arch, Kryta.

Another option is 'ferrying' in which you'll be in the party of a character who is on the quest which will transfer you. You haven't accepted the quest but because you are in the party of the player who has, you'll be transferred as well.

My advise: don't rush through the campaigns, just start playing prophecies with your prophecies character and nightfall with your nightfall character. Later on, transferring may be a nice alternative.