I am aware of the fact that 别 usually means "don't", but what about :/ the expression 别开生面。 Here, doors it mean "another"? What exactly does it mean in this context?
别开生面 usually means to start something new, or to do something new
别 is used as 另外 (something else), or 别处 (another place, elsewhere)
开 is used as 开辟，开创 (invent/open up/start)
生面 is for 新的面目 (a new face/ a new appearance)
In context, it means to start another style, a new style, or start something new.
别开生面 is actually an idiom which means "to break a new path" or "break fresh ground". In this case, 别 is just part of the idiom.
别开生面: open up a fresh outlook
Yes, in 别开生面, 别 means "other / different" (as in "other way" or "different way")
开 (open up)
生 (new )