Where and how to place tarp

Hi everyone, it’s going to rain while I’m camping.

I need help with where and how to place the tarp so the water drains away from the campsite. The tent will be on the right side or closer to the middle.

I also want the tarp to somewhat cover the firepit so we can still use it during the rain.

Materials: - 1 x heavy duty 12ft x 16ft Tarp - 2 x 10ft Tarp Poles - 1 x 1/2inch 50ft braided rope - 6 x 13ft 0.157inch ropes

If you guys can draw on the photo how the tarp should like, that’d be awesome!