Welcome to Songstuff
It means that songs are reviewed by fellow members, but also that there is an expectation of you to review the works of your fellow members. The board rules (at the top of the critique board listing) also state a minimum number of critiques you are expected to perform in return for posting your work for critique.
Giving critique is perhaps more important than receiving critique as it allows us to work out songwriting tools, looking at works other than your own. Experience at giving critique isn't needed, though if new to giving critique it is a skill in itself that takes some worthwhile effort to learn.
It is something that we all started at some point, so members understand would understand and I am sure you will get help if needed. Other than that there are a number of topics about giving critique and an article or two in the songwriting articles section of the site: songwriting articles
Cheers
John