Need some help with preparing rice for Biryani?

I love cooking/eating Indian food. I have cooked various curries with success, surprisingly!

Now I am going to attempt, for the first time, to cook Biryani.

I bought the mix (gharma masala) in a box and am following the recipe on the back of it.

I am a bit confused with cooking the rice. The recipe says to cook the rice half way and then mix it in with the rest of the ingredients then simmer to thoroughly cook.

I am thinking of cooking the rice in a traditional rice cooker/steamer. The problem is I can not set it to cook the rice halfway!…..LOL

Some tips with this would be appreciated.