The use of am /is /are /was /were

In general, we talk about three levels of people.. 
1st person, 2nd person and 3rd person..
1st person means our ownselves.. It's about talking about our self.. very personal.
If one person is talking about himself/herself, he should use "am"..

I am waiting.
I am going.
I am OK.
I am late.

The immediate person to whom we talk is the 2nd person. We should add some plurality to give some respect when we are talking to a person. consider the following...

You are good.
You are going.
You are living.

If we talk about some other person / thing in a situation, in singular sense, we use "is" and in plural sense, we use "are"...

He is going.
He is playing.
She is playing.
They are standing.
The rose is beautiful.

NOTE: This is only in the case of simple present tense and in present continous form. In simple past tense and past continuous form, am / is / are becomes was / was / were respectively.

I was waiting.
You were coming.
She was standing.
They were going.
The roads were broad.