what is j'ai and when to use it, explain it like for a 5 years old
J'ai is a French word that means "I have" in English. It is used when you want to say that you possess something or when you talk about something you do.
For example, if you have a toy and you want to say "I have a toy," you would say "J'ai un jouet" in French.
Another example is when you want to say "I have a cat." In French, you would say "J'ai un chat." So, j'ai is used to talk about what you have or what you do.
Just remember that j'ai is used to say "I have" in French, just like "I have" in English.