Learn French: En utilisant son agenda, elle est plus systématique. - By using her planner, she is more systematic.

While the direct translation is "By using", the gérondif en utilisant acts as a condition in this context. It implies "If she uses her planner, she is more systematic." The gérondif can often replace a conditional si (if) clause to express how an action enables a certain result.

Does agenda mean the same thing as the English word "agenda"?

No, it is a classic false friend! In French, un agenda is a physical or digital planner, diary, or datebook used for scheduling. If you want to talk about the agenda for a meeting, you would use l'ordre du jour.

Why do we use son for son agenda when the subject is elle (she)?

In French, possessive adjectives agree with the noun being owned, not the owner. Since agenda is a masculine noun, you must use son. Additionally, even if it were a feminine noun, you would still use son because agenda starts with a vowel, which forces the use of the masculine form to make pronunciation smoother.

Just as a refresher, how exactly do we form the gérondif en utilisant?