No problem at all.
For being a signaller on PL1 (main server), you need to have driven there server for over 400 km and you are then only allowed to play on sceneries that are on or below your level.
It's not that much of a problem if you don't speak Polish as most users speak quite decent English in my opinion but knowing just a few words and phrases makes your life a lot easier (don't worry, you will learn them quite quickly).
You can also play on the other servers without any requirements but you will need some other people to make it fun.