How close are the park from the pool, and at what time we can be there to find a good spot..?

The pool opens at 11 AM, so if you want a good spot, be there before 11 AM.

Close to the pool,we can find tables,and make some BBQ?

If you want good parking for the pool I would say be there by 11. And to get there just follow the signs

The pool is inside the whole park, you just have to follow signs to get to it once you turn into the Nockamixon park entrance, it's not too far, you could walk from the pool. There are many different parking lots. You can go at anytime really since there is so much parking, but if you are trying to get good parking near the pool I'd say go earlier in the day.