Welcome. We're a small, but friendly forum. So, feel free to post/chat.
As MetalPredat0r explained, I highly recommend watching the 2011 anime first to introduce yourself to the franchise if you haven't seen it yet. That's how most of us got into Idolm@ster. Then, afterwards go through the games, music, manga, movie, OVA, drama tracks, etc.
I also highly recommend you playing the main games for Idolm@ster (after watching the anime). The latest one is One for All for the Playstation 3. So, One for All is best for those who are starting out the franchise.
We have guides and people here can be a source of help too. Don't let lack of Japanese stop you from playing the games. I don't know any Japanese other than a few words/phrases from watching anime. Yet, I completely enjoyed the games. After going through everything on Idolm@ster (animes, games, music, etc), you might even stop liking other franchises since Idolm@ster is just that good. At least that's how it was for me.
I must commend you on trying to learn Japanese. There are other people here who are doing the same, and it's amazing how much talent you guys have to learn a new language. Unfortunately, my brain capacity is full, and I can't learn anything else without upgrading my head.
It seems you like Nintendo games. I'm assuming you own a 3DS? We also have people here who enjoy these games as well. We have topics for gaming and anime if you want to discuss.
I ran out of things to say, so sorry about that. But, I'm sure you will make a lot of friends here. Especially those who are learning Japanese and contributed a lot to this site.
