What is the correct way to place the hands between the two prostrations and in the first and last two Tashahhuds? Does it differ from the way they are placed in the first Tashahhud? And what does Al-Albani’s saying "to place the left palm over the knee and lean on it" mean, despite his prohibition of leaning in the first Tashahhud?

The placement of the hands during the sitting between the two prostrations, and in the first and last Tashahhud (definition), is as mentioned by Imam Muslim: that the Prophet (peace be upon him) when he sat in prayer, would place his left hand on his left knee, and his right hand on his right thigh, and he would point with his index finger, placing his thumb on his middle finger, and would make his left palm grasp his knee. Al-Nawawi explained the grasping of the knee by the palm as the curling of the fingers around it, and the wisdom behind it is to prevent fiddling. As for the forbidden leaning, it is placing the hand on the ground and leaning on it while sitting.