The solid leg most of the time is the leg that supports most of your weight. The opposite of the solid leg is the empty leg. usually, if the right leg is the solid leg and the left leg is the empty leg, then the left hand will be solid and the right hand will be empty. Actually, the leg where the push point is in is the solid leg. Also, the hand where the lead point is in is the solid one.
How can the leading point and push point be on the same side? How can your opponent know ahead of time which side is solid or empty? The answer is open/closed. The relaxation of the body makes opening and closing happen in an instant. All control is in the mind, which directs movement. Therefore, the reaction force from the push point at the leg will go through the body and shoulder to the lead point at the hand.
