I have not done

[hwils66]

I'm rather confused about all the verb conjugations in Spanish. How would you say "I have not done. . ." in Spanish?

[Rusty]

I hope you've found the conjugator page here in Tomísimo. There are other sites with conjugators, too.

The tense you're looking for is the indicative present perfect (perfecto del indicativo).
[has/have + past participle]
This is the first of the seven compound tenses. (There are also seven simple tenses.)
Here is another page to get you started on verb conjugation.

No he hecho = I have not done
Negation (no) comes first.
He is the 1st person singular form of haber (auxiliary, to have). This is the first half of the compound verb.
Hecho is the past participle of hacer (to do). This is the second half of the compound verb.

[hwils66]

Thanks. I would have never figured that out.

[Rusty]

De nada.

[sosia]

Rusty's right, and the verb explanation is good.
But saying only "No he hecho" it's not OK, you must refer yourself about what you have not done.

usual forms
No lo he hecho. (I have not done it)
No he hecho nada (I have "not" done anything)

Example:
mother ¿Has hecho la tarea? (have you done your homework?
hijo: No, no la he hecho (no, I have not done it)
Saludos