Hi ProMaster,
I think the key point of this lesson is that the infinitive form of the verb is generally used in French where the present participle (-ing) is used in English. So for example, in English we might say "Studying French is fun", a sentence that uses the present participle "studying". In French, this same idea is expressed as "Étudier le français est amusant", using the infinitive form "étudier" (to study).
Another example in English is "I hate waiting", which uses the present participle "waiting". In French this idea is expressed as "Je déteste attendre", using the infinitive form "attendre" (to wait).
In English, we can sometimes choose between using the present participle or the infinitive form. For example, the meaning of "I hate waiting" is similar to "I hate to wait". My understanding is that in French we must always use the infinitive form in this situation.

I hope this helps.