Benvenuto Dani!
Don't worry about your English, there are quite a few of us who grew up using another language and we're all doing just fine. Here's the info you asked for:

Danger: The only way you'll cut your throat with a straight is if you're comitting suicide. If you're not killing yourself or immitating Van Gogh, the worst damage you can inflict on yourself is a bad shaving nick with a small scar. That's only if you're not careful and/or shaving with a dull blade.
Razor: Kamisoris are ok razors, most likely made by DOVO but nothing spectacular. That 5/8 full hollow that you got may not be the best choice for your heavy stublle. For that, I'd recommend a 6/8 or larger wedge. You want to talk to Randy Tuttle, Bill Ellis and Joe Chandler if they have something like that in stock. They sell theirs shave-ready.
Sharpening: When you buy a new razor, unless it's from a honemeister or a company that has one available, it will not be shave-ready. You will have to send yours out for sharpening. Lynn and Joe offer those services and get some great reviews. I don't know if anyone in Europe does the same. If you want to do it yourself, either to get new purchases shave-ready or to maintain the sharpness of your razors (with heavy stubble, they will last you about 5-10 shaves), you will need a hone and/or a pasted paddle-strop.
The best: If you have hundreds of Euros to burn, go visit Maestro Livi and get one of his beauties right off the forge. You won't have to leave Italia, and he's one of the best if not THE best modern razor-maker around.
Performance: Shaving with a SE will give you closer shaves than any disposable cartrige razor around and you won't have any ingrown hair problems. You will actually ENJOY your shaves.

Most importantly: Read through our help files and the forums to get more specific information. You'll have a blast!