What is the difference between modal verb and helping verb(is, am, are etc)?

Dear Teacher
It is a bit complex for me to differentiate modal and helping verbs. I want to know what is the actual difference between modal verbs and helping verbs. So please inform me as early as possible.

Thanks
SaadTariq

All modals are helping verbs but not all helping verbs are modals.

Do you understand? Do here is a helping verb, an auxiliary to the main verb, but not a modal.

I got your point but there is a bit problem. It means modals are helping verb so what is helping verbs.

Open this link:
Helping Verbs :up:

A helping verb, also called an auxiliary verb, is used to show tense, make the negative and form questions. Helping verbs don't have any meaning though, while modal verbs can exress obligation, ability, intention, etc.