This is just a basic pouch - same design as a peanut shell (for example). Google Jan Andrea or Sleeping Baby Productions for instructions on how to make a pouch. I must say, merino wool would be a lovely fabric for a pouch for a newborn - I imagine it would have a bit of give in it depending on the weave so you may find it less supportive or that it sags or gives a bit as bubs gets older. There are some very supportive wool wraps but if you are thinking of getting one perhaps ask the manufacturer how much give to expect from the fabric. As a pouch is not adjustable and must be correctly sized to the wearer this could be an issue. I'd also find out about ease of washing.

They do look lovely though.