[Tlhingan-hol] I'm new, and confused by -lu'

[IH]

Hi, everyone! I'm a complete beginner in learning Klingon; I started
last week. I'm using The Klingon Dictionary and looking online for
help as well.

I'm having trouble understanding the use of the suffix -lu'. I
understand when it's used for passive voice, as in the example from
TKD:

Daqawlu'taH, "you are to be remembered"

However, in some other examples I have no idea why it's there, for
instance another example found just under that one:

HeghqangmoHlu'pu', "it made him/her willing to die"

Should I interpret this in a passive voice, as, "he/she was caused to
be willing to die"? Another confusing one is not from TKD, but I saw
it on the kli.org website:

Heghlu'meH QaQ jajvam, "Today is a good day to die."

Here it seems like -lu' is letting us know that it's a good day for
some indefinite subject to die. In English we just use the
to-infinitive for that, but I guess Klingon doesn't have infinitives?
So is -lu' a common way to form something similar to an infinitive?
What about the option of making the verb a noun (I don't know how,
perhaps using -ghach, or using nothing at all) and then since you
can't use -'meH anymore, using -vaD? Or would that be wrong?

Thanks,
-qulcha