Valve's 4 official CS2 Train smoke lineups (Ivy, A Cross, Long Dog, Z), each on the radar with where to stand, where to aim, how to throw and a setpos line to practise.
Start a private match on Train (offline with bots, or your own server), open the developer console and enter sv_cheats 1. Then copy a lineup's line and paste it into the console: setpos puts you on Valve's throw spot and setang turns you to face the aim point, so all that is left is the throw itself.
Some of these lineups use the Grenade Line-up Reticle: with the grenade in hand, hold the fire button until the reticle appears, then line up the tick the instructions name.
These are Valve's official lineups in CS2: the positions, angles and instructions come straight from the grenade guides the game ships for Train, not from community guides. The names of the places they land on are on the Train callouts map.