There is a flying club at Coleman AAF in Mannheim. I haven't looked into it but if you call base ops there you can probably find the contacts. I've been flying in Germany / European central region for almost 4 years, what specific questions have you got?

Airspace takes some getting used to, if you are on an IFR flight plan you will rarely (if ever) be cleared for a visual approach even if you see the runway 20 miles away, and you hold one minute outbound not inbound and you will quickly realize that is the only sensible way to hold.