"Akira Yoshizawa. Japan's Greatest Origami" is a great place to start. it has models ranging from very simple to medium complexity. From there you can look into popular authors like Michael LaFosse (who appears in the documentary). He has many books for beginners (his butterflies are very famous). Once you are confident on your skills, get an insect book from Robert Lang to experience the Dunning-Kruger effect in full force.
For kids, it depends on their age. Mine started around 5 and 6 with small origami kits I bought in amazon (printed in creases makes things easier). For older kids you can find many books with specific themes. Just find one that your kid is interested in (animals, boxes, Pokemon, Star Wars, etc). They all tend to be rather simple.
Also, avoid printing paper. It only works for very simple models. Tuttle publishing sells some nice packages with 100~200 sheets that are nice for simple to medium models.
You can also find tons of free diagrams on the internet. /r/origami in Reddit also has a nice community you can check out.
-Edit
I forgot to mention Jo Nakashima. He has a youtube channel with great videos to follow.
For kids, it depends on their age. Mine started around 5 and 6 with small origami kits I bought in amazon (printed in creases makes things easier). For older kids you can find many books with specific themes. Just find one that your kid is interested in (animals, boxes, Pokemon, Star Wars, etc). They all tend to be rather simple.
Also, avoid printing paper. It only works for very simple models. Tuttle publishing sells some nice packages with 100~200 sheets that are nice for simple to medium models.
You can also find tons of free diagrams on the internet. /r/origami in Reddit also has a nice community you can check out.
-Edit I forgot to mention Jo Nakashima. He has a youtube channel with great videos to follow.