Are your tubes powered from both ends or one? The tubes should have come with a wiring diagram. If powered from both ends, incoming black goes to one end and white goes to the other. If powered from one end, the socket gets black to one side of the terminal and white to the other for both tubes. Twist and pull to remove the existing wire from the sockets. Google the brand for wiring diagram if you don’t have it. The tubes are in parallel.
Here is a video. Be sure to use un shunted sockets for single ended type tubes.
