I wanted to try ultima 4 again and pplay it to 9 but im stuck at the start, I have a fighter and the starting area is on an island
I use the moongate and i end up in skae brea but thats an islanf as well. How do i get off those islands

Moongates correspond to the phases of the moon, not when you use them. Look at the top of the view area for the moon shifts. The first one determines what moongate is open, the second one declares the destination. You have to download the manual or look up the maps online to determine what phases lead to where.

For example, a left crescent on the right most moon will send you back to Britain, a full moon to Minoc, etc. You WILL need a ship in time though. Moongates can't go everywhere.

Another way to get off and island is to die, then you'll be resurrected at Caste Brittania.

Or you can wait for a pirate ship...

Thanks all i let myself killed unintenditly and walking around britain to look for the shrine mantra but how do i get there
the only way i can get ti the shrine uis trough the swamp wich gets me poisoned

which is what Curing is for. RTM. Healers or party spellcasters with some garlic and ginseng (which you start out with) can take care of poison.