how do i unlock strand?

[plush ledge]

i did the campaign quest and now im stuck on this guy named Nimbus. he only offers me a lightfall quest but i dont have lightfall. anyone knows where i get the strand thing?

[smoky heath]

u need lightfall

[plush ledge]

i need the expansion for the subclass?

[smoky heath]

yes, same goes for stasis - beyond light

[plush ledge]

ight time to drop destiny