I have the knowledge of how to use these words.

Past Tense:

My mother had the knowledge of how to use these words.

Future tense:

If you learn from this, you will have the knowledge of how to use these words.

Future pluperfect.

If you then forget this lesson, you will have had the knowledge of how to use these words.

To sum all of the answers above and to make it easier to understand here is a shortcut to it…

HAD means something that you have already done, something that you did yesterday or the day after or in the past HAD also means something that you had but then somehow you lost it

HAVE means something that you have to do today, right now or in the future also means something that you have got right now.

HAD is the past tense of HAVE

HAVE is the present tense of HAD

(Here is a good example)

HAD- I had a good memory of how to use the words had and have but now i forgot how to use them.

HAVE- I have a good memory of how to use the words HAVE and HAD and right now i still remember it….

And i hope that this answered your question because there isnt a wrong answer above all of them are correct…

Have = Present Tense/Future

Example:

I had to get my sister yesterday.

I have to get my sister today/right now.

i HAD a dog. the dog died.

have = present tense.

i HAVE a dog. the dog is still around.

another way you can use them is:

HAVE you given him the book? as in, did you give him the book YET?

HAD you given him the book? as in, did you give him the book some time in the past?

have is the present

I have a life.