Salaah of a sick person

Q: Can you give me the description of the different actions (Roukou, Qawmah, Sajdah, Jalsah, Qa'datoul oula, the moment we stand up between 2 rakaats) that someone does when he performs namaz in the position of sitting?

Q: Is it permissible to sit on the chair and perform salaah? If yes, what are the rules regarding sitting on the chair? If sitting on the chair and reading namaaz is permissible then is it permissible to sit on the chair and eat?