If you are new to GI, then you will need help, help with answering your question and help with friendly games in bigger stadiums. Answers you will receive in the newbee forum. Help with friendlies you will receive here.
Some of the veterans are willing to accept each challenge from starting teams. So if your stadium has less than 1500 seats (summarized VIP/Exec/normal seat) you could try to challenge one of these teams, some managers have own restrictions, pls accept that. Also this intended for real newbees. So if you are a "lazy" owner that stays here for months and did not built the stadium - don't expect that the mentors accept your challenge: