CLEAN re-install Galaxy Note

Hi All,

I'm totally new in android community and I'm just a plain user. no stunt expert. No different with any noob lady who just use the phone for sms, whatsaap, calls and photos.
Lately my galaxy note have been super sluggish! Been notice it's slow since upgraded it to Jelly bean but recently it is really getting onto my nerves!!! when I can't even type correctly on whatsapp.

Can someone please guide me how to thoroughly clean format (reset) my phone and re-install it with latest built?

root or recommend to use the stock built?

Please help...

Jamie