Having spent the better partof the last 20 hours with this game i'd like to clarify some things : Even after the patch there are still some bugs but asinde from the initial "the missions don't work" thing it's nothing world shaking or gamestopping., expect a patch within the nxet few days.
"The missions don't work! / I can't reenter my ship in dock!"
That's something I've read/heard quite often and the documentation/ingame help don't really adress this so here's what I did:
After docking at Kiel and saying good bye to your old commander you'll notice 2 guys standing around you can talk to (press ALT to outline them with a yellowish frame). THe one on the left lets you upgrade your sub for prestige, the one on the right (dressed in a uniform) let's you a) choose a mission and b) make a sortie. That's how you get back on your ship and out there.
Now choosing a will bring up the mission briefing but you won't see any icons to choose and accept anything, that's what most people report as the dreaded DRM kicking in or having to download stuff. Now thta's a complete pile of steaming bull...
It's juxt another bug in the game, simply quit the game after the tutorial, restart the campaign and click "skip tutorial" when prompted, you're standing in the dock in front of the flotilla captain and voilà, miraculously the missions work.