When we pray salah, we sit in different positions depending on what part of the prayer we are in. When we first stand up, we raise our hands to ask Allah for help and guidance. Then we recite some verses from the Quran and bow down to show our respect and submission to Allah. Next, we stand up again and recite some more verses before going down to the ground, putting our face and hands on the floor to show our humility to Allah.
After this, we sit down on our heels for a little bit to take a break and catch our breath. It's like taking a quick rest before continuing with the rest of the prayer. Then we stand up again, recite some more verses and bow down again. We do this a total of two times before going down to the ground again in the same way as before.
Finally, we sit down again and recite some more verses before giving our salam (greeting) to end the prayer. Sitting in salah helps us to take a break and rest our legs, but it's also an important part of the prayer and shows our obedience and respect to Allah.