The simplest way of cooking rice as a part of a main meal is to boil it. There are two main methods: the absorption technique, and the free simmering technique.
This you need to experiment to get the amounts and time correct. Here's the technique that works for Basmati rice
- Measure the rice into a saucepan that is at least four times as big as the amount of rice you need.
- Wash the rice: nearly fill the saucepan with water, and stir the rice. The water should become somewhat cloudy as some of the starch is washed off the rice. Drain the water, and repeat a few times until the water is (almost) clear.
- Drain the rice. You don't have to be too exact about this.
- Add cold water to the pan - about double the volume of the rice.
- Add a pinch of salt (amount depending on the amount of rice) and any other flavourings. (A crushed cinnamon blade is nice.)
- Bring the rice to the boil, cover the pan, and let it simmer for ten minutes.
- Turn off the heat, and let the rice stand for five minutes to absorb any remaining water and become soft.
This technique works for different kinds of rice but you need to work out by trial and error how much water to add, and how long to let the rice simmer. Instead of water you can use stock to flavour the rice.
Free simmering 
This is a much simpler technique.
- Fill a large pot with water (at least five times the amount of rice to be cooked) and bring to a boil.
- While the water is coming to a boil, wash the rice (as above)
- When the water boils, add salt to taste and add rice.
- Boil the rice gently until it is cooked to a firmness you like (boil until swollen). Do not stir while boiling. Do not over cook (do not cook so long that it bursts).
- Drain as gently as possible (do not stir), cover, and allow to "soak." Lining the inside of the lid with a cloth or paper towel assists in achieving fluffy rice.
- It can soak off heat for 10 minutes or so and be ready to be fluffed with a fork and served. Or it can soak on very low heat for up to an hour, if necessary.