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?
Yes that reset your coinage. If your whole stack staked in one go, all your coins have to mature again so you can just as well move everything out out and back the moment they become available after the stack. When the become sliced up a lot and staking at different times it becomes tricky to move them because you might lose several hours on portions of your coins that have been gaining weight a long time but not yet staked at the time of moving your stash.