Ok so this is the way i did it, and along the way you will unlock some other achievements too
Okay then to start i suggest picking from either
Celtic or Rangers, then start the career.
Once in you can purchase players but only if you really want to as its not necessary.
Right the tactic is to save before your next match so that if you lose you can reload and replay the match, so this way you can win every match. Keep playing matches until you come to the end of the season (Red calender item) and you will have unlocked three achievements for 70G... This took me about 2-3 hours