"Duo, do you know how to skate?"
Translation:Duo, tu sais patiner ?
It's just a difference between French and English. In French, the "how to" is already implied in the construction "savoir" + infinitive verb, at least when the infinitive verb describes a skill. "Savoir comment" + infinitive verb is possible when the infinitive verb describes a process rather than a skill. In some cases, both options are possible.