Our state 4-H sewing group has made them before. These were easy to make.

As a Mom whose sons have used them. There are a couple pieces of advice. Double check to make sure the fabric that you use feels good to that child - there are many children who deal with sensitivity issues (I have one who didn't like the feel of fleece)

A cheap way to fill them is with old torn-up towels. That is what these where filled with and they really were heavy. The one that we had was about 20 pounds which was more than 10% of the body weight but it was comfortable to the child(ren).

Be sure to sew divide lines otherwise the filling can shift to just one area of the blanket.

The one that we had was sewn into a rectangle of about 4 feet finished (it was originally longer but once it is stuffed, it becomes smaller as the pockets round out). Then sewn across to divide. The blanket closed with velcro which was nice because we could adjust the weight if needed.

The information that we have been told is that there is suppose to be a doctor or OT to approve of the use of a weighted blanket.