Uhmmm... Airlayering is not the most straightforward technique, however if you want to learn about it, here is a good link:
bonsai4me.com/AdvTech/ATLayering.html
Now, one more thing... I´m not too experienced with conifers, but before doing nothing to your tree, you should properly inform yourself about its features. Care guides wouldn´t hurt either. As I said, I´m not sure, but I think airlayering is not the best technique to apply on conifers to promote their propagation:
"
PROPAGATION: Sow seed of species outside in early Spring, the seed needs to be exposed to frosts to germinate. If the seed is fresh, germination can be rapid. Cultivars need to be propagated by grafting in late Winter."
Anyways, care guide on pines in general and on Mugo Pine in particular, here you have them:
www.bonsai4me.com/SpeciesGuide/Pinus.html
www.bonsai4me.com/AdvTech/ATMugo%20Pines%20Indepth.htm
Hope all these might be of help,
Alain
