NOT is easy -- it's the opposite of whatever you define the condition as. If the (only) restriction is "SOBRIETY = 99", then that means link only visible when SOBRIETY is equal to 99. With NOT checked, link is only visible when "SOBRIETY != 99", or when SOBRIETY is NOT equal to 99.
OR gets a bit trickier. Without OR checked, ALL restrictions MUST be met in order for the link to show up. So, let's go back to your example: "SOBRIETY IN 99,100" and "RESISTED=0". Both must be true for link to be unrestricted. If you have 100 restrictions, then ALL 100 must be met. However, if *any* one of those restrictions are marked as OR and they are true, then the link will show.
Note that it is very possible a bug could show up with this. So, if you notice it behaving differently, please advise.