This is a summer project that looks good in January. Pine chairs kids will love. All made with 3/4″ (actual thickness) pine. Start with 2 side pieces 3 3/4″ x 20″ beveled at front and back so back will sit on the ground, front elevated to 7 5/8″. Cut 3 pieces for seat bottom 2 1/2″ x 12″, fasten to side pieces with 1/2″ space between, with back of seat 8 3/4″ in from the front.
Cut 2 legs 1 7/8″ x 11 3/8″ and attach to outside sides, fastened from inside, so top of side piece is 7 5/8″ off the ground. Cut and fasten 2 1/2″ x 13 3/8″ front apron so its top is flush with seat.
Cut back pieces – 2 @ 2 1/2″ x 14 3/8″, 2 @ 2 1/2″ x 15 1/2″, and fasten them to middle back support (2″ x 14 7/8″) and lower back stop 1 1/8″ x 12″. The top of the middle support is 6 1/2″ up from the back bottom. Use a 9/16″ spacer for the back so the assembled back is 11 5/8″ wide. Cut two arm rests 2 1/2″ x 14 1/2″. Fasten lower back stop to sides and fasten arm rests so they overhang the front legs by 1 1/4″, and the projections of the middle back support by a like amount. Bevel the ends of the middle back support where the arm rests attach. Nail and glue all joints. Paint as desired.
Add arm rest braces 1 3/8″ x 3 5/8″ as above and below (closeup of side view of arm rest brace, front apron, etc).
Closeup of back middle support piece showing overlap of arm rest and bevel of support.