Lajin is easy to learn. Be sure you do it in a proper sequence. Pace yourself and slow down to prevent from unnecessary muscle strains.
It does not matter if you cannot fully stretch out your arms or make your upper foot close to the pole or wall. Stretch to the point where you can tolerate the pain and get your body used to the feeling of Lajin.
If your knee falls down when you are raising it up, you may fasten it on the pole with a towel or cloth. If your foot cannot touch the ground when put down, you may weight it with sandbag or other heavy stuff, or you may step on several books or a stool.
Phase 1: The foot on the ground may step on books in order to better support the foot up against the pole or wall.
Phase 2: Remove a book or two to lower down the supporting foot.
Phase 3: Continue to remove books.
Phase 4: Congratulations! Your supporting foot is finally on the ground now.
At home or in the office, it is feasible to do Lajin with chairs or other furniture.