By reading your post, something tells me that your  English level should be beyond the question you just asked, and able to categorize the tenses already.  

There are 3 basic tenses: Simple past – present – future

There are past progressive- present progressive- future progressive.

Then there past perfect- present perfect –future perfect which is not commonly used.

I am curious, may be I am missing something. Why do you have to memorize the tenses?

We should be able use it according to the sense of time. 

You are walking – you are doing something at this minute. So it’s present progressive

I walk 2 miles everyday after work.  Simple present, used  to reflect a routine.

They were watching TV when you called last night.- Simple past progressive.

The perfect tenses are more complex and you may have to do some reading and studying on your own.

Here is something which may be helpful: http://www.englishpage.com/verbpage/presentperfect.html