Add the salt, just like you would when seasoning water for pasta.
Cook the basmati, with the lid on, at a low boil until soft and tender.
Strain the rice through the colander.
Video
Notes
Use plenty of water to rice, as you would when cooking pasta.
HOW MUCH SALT - add 2 tsp kosher salt per litre/quart of water for perfectly-seasoned rice (or pasta, potatoes, etc.), or use half that amount if you prefer barely-seasoned grains as a blank canvas.