Infinitives in French are basically the dictionary forms of verbs (the "unconjugated" forms).
They're the forms from which we conjugate all verbs.
Infinitives can generally be classified into 3 groups:
The first two are quite simple.
ER and IR verbs tend to follow simple rules that are easily memorized.
The third group is a little more of a headache for beginners.
These are irregular verbs, and oftentimes they will even use the same endings as ER and IR verbs just to confuse you!
See these lessons:
French participles serve to modify the noun.
They can work as adjectives or even nouns themselves - what's important is that you remember they're main role is modify a noun.
They follow simple rules in French.
Participe présent: verb + -ant (e.g. jouant / playing)
Participe passé: verb + -é / -i / -u (e.g. j'ai couru (I have run), j'ai fini (I have finished), j'ai pleuré (I have cried)).
Unlike the participles mentioned above which are noun modifiers, gerunds modify the verb.
Gerund verbs are basically -ing verbs.
E.g. walking, running, yelling, eating, etc.
Here's how to form gerund verbs in French:
Take the the participe présent of a verb and add the word en to the beginning (e.g. En courant (running)).
Think of it like this: "in [the action of]" + verb.