Where can I add xposed modules to systemless xposed framework?
From Magisk tap downloads and search for Xposed


Choose Xposed version corresponding to your Android version- choose the version by rovo89

Tap on the module, on the next screen it will prompt you to download an installer. Do that, give permissions for installing for external sources when prompted. Go back to the earlier screen and install. Let it do it's job and reboot.

You would get the familiar Xposed installer. You are now good to install systemless Xposed modules