Hi Carolyne,
Mode Indicatif is indicative mood in English grammar and describes a collection of tenses describing facts that are happening, have happened or will happen in the present, past and future.
What this lesson illustrates is the present tense which we use most often of things you do, (or are doing) using some irregular verbs which conjugate in their particular way and being used in the present tense of the indicative (mood).
In time you will learn different present tenses of different moods and this is to distinguish them from each other.
The indicative is the realm of certainty and facts.
I have tried to simplify as much as possible.
Hope this helps!