Newbie to Arcade

I'm a newbie to arcade, so please someone with prior experience please teach me about it, so that i can also participate in this activity.

Well, first of all you have to have at least 25 post to be able to play games in the arcade. If you manage to get the first place on a certain game you will win 500ddp. That is basically all you need to know.

how do i play and where do i play the arcade games. do I need to donate points to play arcade

No you don't need to donate points.
If you want to play a game once it will cost you 10 DDPoints. The points don't have to be in the bank when you play games.
If you brake a high score at any game you will win 500 DDPoints.
Remember that each time you play a game 10 DDPoints will be taken from your account.