Interesting position you are in here..
There is simply too much to teach over a post or two, but I suggest learning how to use your flash as a fill-flash first.
Check DSLRTips or even YouTube and search for fill-flash techniques. This can come in handy when you go to the beach.
As far as studio work, do you want to create a "full" studio with strobe lights and backdrops etc'. Or do you want a more portable solution/outdoor work with a couple of external flashes and reflectors?
So in other words, Lite studio? or full-out studio?
How serious do you want to get into portrait and studio photography?
I already searched on Youtube a couple of times but couldn't find much. But basically what I want to do is start taking pictures outside, for example at the beach. And yes I'm talking about taking pictures of people at the beach, I already have a model who is willing to work with me. So that's pretty good! Uhm studio photography is going to be a problem I think, unless I find a video or a forum or what so ever to explain me what I need and how to work with everything. I think I would like to get pretty serious in portrait photography, I have different interests but portrait photography is definitely one of the top ones. I should really get to know how to work with light etc. Because I'm getting a lot of requests lately to do photo shooting. And I would like some outstanding results
. So if you have any tips just let me know