This smoke is a variation of a smoke posted here: https://www.csgonades.com/nades/mirage-smoke-snipers-nest-from-t-spawn

I found this lineup to be more consistent than the one posted above.

Go to the left side of the trash can in T spawn. Find the rightmost wooden beam and follow it down to the top of the railing. Crouch and walk forward until you get halfway down the railing. Jumpthrow bind.