Progressive tenses are used to discuss ongoing or continuing actions. They can also be used to talk about an action that is, was, or will be occurring at the same time as another action. The progressive tenses use a form of the verb ‘to be’ plus the present participle of the verb.

Present Progressive Tense

The present progressive tense is, typically, used to talk about something that is happening right now. It can also be used to talk about a future action or an action that is occurring at the same time as another one

I am walking to school right now. (current action)
He is walking to school tomorrow. (future action)

Past Progressive tense

The past progressive is used to describe an action that was occurring at the same time as another past action.

Yesterday, I was walking to school when you saw me.

Future Progressive Tense

The future progressive is usually used to describe an action that will occur at the same time as another future action. It is formed by using will be + present participle

Tomorrow I will be walking to school when you see me.