part 1 is so far away for completely scanned 3q2t5t

can i read part 2-3 before part 1 or ill miss something

No idea, forums on MU are dead, try other forums like mangafox etc for quicker response

You should watch the anime of part 1 first, I think. It must be more-or-less identical to the manga, hence why this part of the series hasn't been scanlated.

You can find rips of the licensed version in... less reputable aggregators.