We have taken down the deck and pergula and want to add an addition to the existing 10'X22' cement patio, all one level, the same size as the deck. The patio and cover will also extend past the
windows of the den to cut down on the sun exposure. We want to add steps down to the yard and a walkway to a fire pit but we don't want a bannister around the patio as it would block the view of the lake at the higher height of the patio. We'd like help with a nice design for the patio and fire pit area and advice on where to put the firepit. We don't want to finish and it not look nice. Any suggestions. Thanks.

If it were me....
I would of left the existing except.... Taken out the treads of the decking and added trex. Beefed up the pergola to accept a sun room on top, with an entrance from interior and exterior. Then screened in the bottom. The view of the lake would definitely be much greater from above.

Is the deck pictured what you took down, and the concrete part the patio you're referring to?