MM transactions techical help

Hi all,

I need to learn some MM transactions but I could not find any helpful techical document on these trans.

For example how to use MM01, when to provide a number for material or not to provide a matnr.

And step by step procedure to create a material.

Note: I am not asking MM01 transaction, it is just an example,

I need more trans to learn like MM01.

Please pay attention in posting that mostly used transactions be sent.

Thanks.