Need help to get started with Eldar and Seer Council

After approximately 20 years since I last painted an Eldar model I had to come back with the release of the new combat patrol box. It contains the two units that got me into Eldar from the beginning (dire avengers and warp spiders).

The only models I still have left are a wraithlord and the old metall Eldrad. I've always like the theme of Ulthwé, so would like to expand into a Seer Council list. But I'm a little lost of where to begin.

At the moment I have the combat patrol (and a box of warlocks) together with my old Wraithlord and Eldrad. How should I equip the models in the combat patrol box and how should I expand if I want to stay in theme with Ulthwé?