WELCOME ABOARD!
At first glance I would have said you should load Op Monsun and it's patches first, but none of that would affect the 'problems' you're having.
Op Monsun adds a brilliant campaign and combat experience, but no SH4 mods that I've seen give the 'extras', the sights and sounds that come with the major SH3 supermods. It's the best mod for SH4 in the Atlantic, and what it does give is great.
As for the location star being in a different place from the grid given, I'm afraid that's an SH4 problem that hasn't yet been resolved. Go to where the star is, and stay in that vicinity the required time. When it turns grey, radio in. You'll get a new location. After one or two times of that you'll be ordered to patrol where you think the enemy is, so you're on your own.
SH4 comes with latitude and longitude coordinates. UBM (1.5) adds the KM grids, right down to the 4-digit locations. I don't know of any way to get rid of one or the other when playing German, but I haven't asked before because I like having both.
And no, there is nothing like Commander for SH4, which drives me crazy because I like having all those different crew names and I'm the guy who keeps adding more historically correct ships to Commander.
Anyway, SH4 with OM takes a little getting used to, but it is still a wonderful experience.