Long grain rice is the one you want when you need the grains to stay separate and firm. For salads, for cold dishes, for anything where the rice is part of a mix rather than the main event.
The method is the same as plain basmati. Rinse well, add one and a half times the volume of water, cook on medium heat without touching it until the water evaporates, then cover on low for two minutes.
The difference is in the texture. Long grain stays firmer and less fluffy than basmati. The grains hold their shape well when cold, which makes it the right choice for rice salads and dishes that sit in the fridge before serving.
If you are making a rice salad, stop the cooking by running cold water over the rice in a colander until it is completely cold. This stops it cooking further and keeps the grains separate and ready to mix.