This video presents an great overview about the basics of using mylar bags for extending the storage life of your food. The presenter goes through issues about using the right sized bags, oxygen absorbers, properly filling the bags, and sealing them using a hair iron.

This video does not present vacuum sealing the bags, but only uses oxygen absorbers.

The amount of oxygen absorbers needed to properly store the food that they reference is found in this list: recommended oxygen absorber amounts