Theory:

THE DIFFERENCE BETWEEN SIMPLE AND CONTINUOUS

There are two kinds of actions used in English grammar.
The first kind is a short quick action that lasts a few seconds, like kick a ball or break a window.
This kind of action is called a SIMPLE action.

The second kind of action lasts for a longer period of time, like doing homework, or cooking a chicken.
This is a CONTINUOUS action.

The SIMPLE action CAN BE REPEATED often, but a CONTINUOUS ACTION is considered to be a TEMPORARY action.
This means it starts at a fixed time, continues for a period of time, and then stops.
This makes it a temporary activity.
That is an important characteristic of continuous actions.

Simple actions can happen in the past, the present or the future.
For example:
He kicks the ball every day.- PRESENT SIMPLE
He kicked the ball yesterday - PAST SIMPLE
He will kick the ball tomorrow - FUTURE SIMPLE.
ED is added to the verb to show the PAST, and WILL is added to show the FUTURE.

CONTINUOUS actions are treated differently.
Firstly they have to be combined with the verb TO BE, secondly they end in ING and finally the moment when the action happens or its duration needs to be defined.
For example:
I am doing my homework now. - AM = verb TO BE, doing = do + ING, NOW defines the time.

This can happen in the past by changing the verb TO BE from PRESENT to PAST.
For example:
I was doing my homework at 5:00.- WAS is the verb to be in the PAST.

It can also be given in the FUTURE.
For example:
I WILL BE doing my homework at 5:00 - WILL BE is the verb to be in the FUTURE.

The PRESENT PERFECT form has the same structure.
For example:
I have been doing my homework for 2 hours - BEEN is the verb TO BE.