Does anyone know how to do: a) a handspring b) an FS rail 360 ..

To do a handspring press X once then press O once.
To do a FS Rail 360 get on a rail then press left or right twice.

To do a HANDSPRING, all you really need to do is press O. You only have to press X if you can't reach the rail. You can also do a HANDPLANT by holding down O. You will need to balance yourself to do this. Hope this helps!

Handspring- go really fast, and tap O by a rail

FS rail 360- while on a rail, hold left or right. Make sure you spin FS, and start with a boardslide, instead of a 50/50

wow that is easy i have been trying to do ubers but nothing has worked for like an hourso im relieved now

To perform a Handspring, all you have to do is to, as what .hack wrote, go really fast and tap O beside the rail, not over it. And also what creaturecourt written, press X if there's a rail above you. To perform a FS Rail 360, "FS" stands for "Front Spin", so as you're grinding the rail, tap X to jump off the rail and spin yourself to the left 360 degrees (means that you'll need to spin a full circle, oh, and position your body as you're facing to the right). That's all you'll need to know! But before I pin down my quotes, "BS" stands for "Back Spin", and it works vice versa.