#living in madrid

Hello guys! :>
Sorry to bother you with kind of random request but it seems I’ll be moving to Madrid for few months and because I don’t know anyone from there I’d like to ask you few things (just in case someone of you lives there or closeby).

Firstly - I’m currently looking for a flat or flatshare. Would anyone possibly know some helpful websites for this?
Also, if there are any things I should know about living in Madrid please tell me!
Secondly - if anyone from there would like to meet I’d be most happy (I need to find some friends :’D)!  
Thirdly - If you have any tips for things I should see or try while in Spain let me know! :)