I really can't see where the tubes are going, but I think the Tee closest to the filter feeds the solar loop, the Tee farthest from the filter is the return from the solar loop. The valve between the Tees bypasses the solar loop (when open) and the valves on the legs of the Tees isolate the solar loop (when closed). The line beyond the farthest Tee is the return to the pool.

How big is the line from the filter to the pool? How's the flow at the pool return? Are you planning to run parallel sections of the 1/2" tubing? Have you thought about how to lay this up for the winter?