1）Put seat cover on sofa, string toward inside
2）Use mirror or hand to put the shorter side into the gap between back and seat of sofa
3）Then put into the both sides of sofa
4）Slip back cover over the back of sofa
5）Straighten the back cover, insert it into middle gap first, and then both sides gap
6）Put the bands back and tie them
7）Rectify some details, DONE !
8）use mirror to put the cloth into the gap