To make a chair, you first take a box. then you turn its Z face by 90 degrees towards the ground. Then you shift drag to make another box above the existing one. Reduce the width of the upper box to 0.05 m to make the seat Rduce the X axis width of the lower box. Shift drag it, to make the back rest above the seat. Place it at the edge of the seat. Turn the lower part by 90 degrees about the vertical axis. Shift drag it to make two legs. Your chair is ready. Put the textures to make the cushions.