You can prepare rice water with any type of rice, though white, brown, and jasmine rice are common options. If you already own rice, whatever kind of rice you have on hand will work. If you want to make large quantities of rice water, you can increase the amount of rice that you use, as long as you remember to also increase the water. Keep in mind that rice water has a shelf life of 1week. Pour water over the rice and swirl the water to remove dirt. Strain out the rice and return it to the empty bowl. Repeat the steps to wash your rice a second time.

TL;DR in Indonesian:
Pilih jenis beras yang digunakan. Masukkan 90 gram beras ke dalam mangkuk. Cuci beras.