How it usually goes? Am I suppose to be matched with a residency and then find an internship or the other way around?
Internship is the first year of residency. In the most simplistic model, when you match for residency it includes your first year or internship.
However, to complicate matters, there are residencies which don't include internship and require you to match to that as well. You apply for both your internship and advanced placement residency at the same time. You cannot start an advanced residency without completing an internship.
How long is the internship and what kind of internships exist (surgery, medicine...). I'm intersted in a psychiatry residency.
Internship in the first year of residency and lasts one year. For residencies which are an advanced match (ie, Anesthesia, Radiology, Derm etc.) you can complete a Preliminary internship year in Medicine, Surgery or something called a Transitional Year which comprises other rotations. Most residencies in Surgery, Medicine, etc. have the internship year included. Psychiatry is a 4 year residency; most programs include the first year.
Is it possible to begin a residency without an internship?
Not if the particular residency does not include an internship or you have not completed it elsewhere.
if I'm intersted in beginning a residency in the u.s. and finishing it in europe, do I have to do an american internship for the residency?
Yes. Most US residencies will not offer credit for any graduate medical training done outside of the US or Canada. Please see my response in the General Residency Forum to your enquiry about doing part of your training here and part in Europ .
I'm sorry for all the many basic questions, but I'm just beginning to plan where to do my residency and I need a place to start...
Thank you so much
No problem asking so many questions, but please do not post the same question on multiple forums. And again, you will find the answer to many of your questions by doing some basic research at the web sites of the NRMP, ACGME, ECFMG and AMA.