Guide how/what to flash to go from Xwrt Vortex to Fresh Tomato?

As the thread title says i am currently running xwrt vortex on my r7000. Whats the best way to get to Fresh Tomato? Which files will I need?

Also, if I want to use my expressvpn credentials do I need to flash just the vpn file for both the vpn and the AIO file???