So I'm currently working on a website, where you can click on "play" and select "your settings" to create a link to a board game also hosted on my website, where friends can join. The whole "create a link" thing is completely new to me and also is the assigning IDs to the different players (IPs) so that if they join

1. their place is taken and
2. if they close their browser they can just open the link again to join (and no one else can join but the person).

The context is not really necessary (I think), I just don't know what methods to use for "link creation": so whether the problem is solved with temporary folders or anything else; and also what methods to use for "ID assignment" (I have no idea what to call any or that, I'm pretty new...).