Demonstration
Step-by-step guide
1
Aim crosshair
Place your crosshair here

2
Throw
Press the keys to throw the grenade
W
A
S
D
Shift
Ctrl
Space
Left clickRight click
Don't hold Shift — run normally
Hint
Move to the third marked T spawn position, align the crosshair with the sky reference above the mid roofline, and jumpthrow with left click.
Practice from exact position
Paste in CS2 developer console to teleport to the throw spot