What do these exercises do?

not really. Those are ment for tonning and building muscle which will help with a beer belly but you need to do way more than that.

Add some cardio like biking, running, swimming, stair master that type of thing.

a half hr each day would be really good but just do as much as you can.

Tone muscle.

They will only build the muscle underneath, it will probably burn some fat, but if you are looking to lose the beer gut, ditch the beer and add in some cardio and make sure it's burning more calories than you are consuming.

Well,

first the remove the excess fat

and then on top of that they build abs.

build abs. x

all i know is that they dont feal good