The Spoonflower Handbook is here!
Cut out the pieces. Make the indicated snips at the concave curve of the neck. You may want similar snips around the convex curves of head, hands and feet - to reduce unwanted stretching and folding of the seams.
Assemble the limbs separately from the torso.
Each leg needs a front and a back piece. Sew, right sides together, down one side, around the foot and back up the other side, leaving the top open. Turn right sides out. Stuff and close. For additional leg articulation, stitch across the knee.
Each arm needs a mirrored pair of pieces. Sew, right sides together, down one side, around the hand and back up the other side, leaving the top open. Turn right sides out. Stuff and close. For additional arm articulation, stitch across the elbow.
Sew the torso, right sides together, up one side, around the head and down the other side, leaving the bottom open. Turn right sides out. Stuff and close.
Attach legs (toes to face and heels to back!) and arms (dangling down).
Leave the limb pieces open at their ends for joining onto the torso.
Only sew the torso across the shoulders and around the head at first.
Insert each right-side-out arm into the inside-out torso in turn; sewing around the armhole, starting from the armpit and looping around the shoulder, so that you can continue down that side of the torso.
With both arms in place, turn the torso right sides out and stuff as a unit.
Attach each pre-stuffed leg as a similar open loop from the outside, making sure they are properly connected up in the middle.