Use the dot and aim 2 bars underneath it.

Nade Time till goes off : 6 seconds
Smoke fade: 24 seconds after throw

Nade Ranking (stars are rated as 5 is the worst and 0 is the best, so the more stars the more challenge/time/difficulty/risk)

Setup Time: ★★☆☆☆ (approx. 5-6 seconds)
Practice till Flawless execute: ★★☆☆☆ (approx. 2-3 attempts till you can hit it regularly)
Cost of Failure: ★★☆☆☆ (Smoke off map, Smoke A site)
Throw Difficulty: ★★☆☆☆ (Easy with practice)

Nade Overall Rating: ★Occasional★
|| Occasional- Someone who has utility occasionally but doesn't practice ||