The process is exactly the same as if you were purchasing an item: click on ‘continue to payment’ and follow the usual steps. Obviously you will not be asked to provide payment details in the end, and therefore you will not be charged for anything.
Vanjir is a fully reversible scarf knit in bulky weight yarn.
Gauge is not crucial - go with what gives the fabric a feel you like.
This is a fast knit with easy techiques, and would be an ideal pattern for an adventurous beginner to expand their skills.