Purva_Narang
Generally it gets announced at the end of the prior, you should be able to see the current ones in the inbox of your profile. It tends to get pushed down a bit by the rest of the spam from WN though so might require scrolling down to see. Typically if you're going to enter it's best to do so at the start, while it's not impossible to 'catch up' half way through chances are higher you won't.