Can I use same apple id and password on ipad2 and pc with Wins 8 on it. Needed to go to PC to ask this Q.

bought my 1st apple 4 days ago. ipad2air - always used Wins8 & MS on pc - so finding apple v different. When set up on Saturday with help from friend used to tablet. I used thumbprint for id - worked for 1 day and now nothing. Also both user ID and pw were written on paper Sat and already by yesterday were not recognised. Just can't suss out this tablet and don't like it already - cost me 399€! ++ 100€ for 2 essential accessories. Any ides anyone before I throw it away?