Clueless

Hi Linles here, 

newbie motorhome users.  We are leaving for some months in spain, (pensioners don't yoy know lol). can anyone tell me if we need a gas certificate for the motorhome and should we get a european gas bottle as well as a uk one, or if that is even possible. Also we have an autoquest 100 and have no idea where the flush is on the toilet system or what  the big round stopper  on the right hand side is for?  Can anyone help.  Please. Thanks.