Best way to stake is after receiving my first reward i should send it to new address?
Yes. The whole amount.
Your existing address will do just fine too.
i just received my first reward. i transferred my whole 10k to my 2nd address. by doing that did i reset my coinage to 0?
you don't have to move them every time you receive a stake reward. only when you stop receiving them or if they start getting really small.
I just send them to the same wallet with a receive address I labelled "refresh"