Before anyone else jumps on the bandwagon with cries of "if you can't remove a seat pad, perhaps you should leave all the servicing to a dealer", I will assume you a very new to the brand or maintenance on these bikes in general and this is a genuinely posed question. If that is the case, then you just have to bend back the seat pad material along it's rear edge, to reveal the bolts underneath, sufficiently enough that you can get an allen key in there to undo them. Forums such as this one (though it's not unique in this case) are ostensibly here to help, so I hope you continue to receive it when needed, as you look to learn more about maintaining your bike in the future. We all had to go through the same learning process at some point.