a membership class is when a new member of a church takes a class on the church. Some of the topics covered in the membership class are: the church's history, the rules of the church, the structure of the church, who is who?, etc.
Here's a list of what membership classes more or less consist of: https://smartchurchmanagement.com/church-membership-class/
The reason why UBF churches/chapters don't do membership classes is because it would be nearly impossible for the UBF "missionaries" to help new sheep "grow" (in other words brainwash). Nowadays it is nearly impossible for UBF to get new members at all let alone committed ones due to advance technology specifically the internet where one can look up all kinds of intel on UBF both bad and good (mostly negative).
Has UBF churches ever done membership classes? Yes but they are EXTREMELY RARE. What I mean is that individual UBF churches/chapters rarely conduct membership classes much less publicly put them online.
Here is a video of Triton UBF's membership class:
As for UBF entity as a whole they show history videos at the UBF international conferences which is the closest thing to a membership class.
Here are the history of UBF videos that were shown at the UBF ISBC 2018 conference:
Sidenotes: The quote that is shown in the 2nd history of UBF video (6 seconds in) "if our world is to be changed, it's going to be at the university level on campus" was never said by Billy graham. In fact that quote was made up.
Google search the quote and you get this https://www.google.com/search?rlz=1C1GCEA_enUS805US805&ei=KayvW9_UMcjCjwSp54nQDQ&q=if+our+world+is+to+be+changed%2C+it%27s+going+to+be+at+the+university+level+on+campus&oq=if+our+world+is+to+be+changed%2C+it%27s+going+to+be+at+the+university+level+on+campus&gs_l=psy-ab.12...66816.66816..86790...0.0..0.108.108.0j1......0....1..gws-wiz.......0i71.8o5EtJDTX3s
In the first history of UBF video about 6 minutes in you see UBF "missionary" Joseph Chung presenting his part in UBF history. He is the father of Joe Chung the 2nd gen who exposed UBF on a blog called exubfjc. Here's a link to that blog: https://exubfjc.wordpress.com/