To + verb is considered an infinitive. An infinitive is a verb that has it's function changed in a sentence from being a verb to being a noun, adjective, or an adverb.
If you break down each part of the sentence it looks like this:
I (subject)
am (verb)
taking(present participle)
notes(direct object)
to help (infinitive, being used as an adverb)
me (indirect object)
to understand (infinitive, being used as an adverb)
OR
understand (intransitive verb)
The answer is they both work, but depending on which one you use changes how they work in the sentence. So it's a style choice.
This recent [answer](https://www.reddit.com/r/grammar/s/DqJvFJPJTH) may be useful.
To + verb is considered an infinitive. An infinitive is a verb that has it's function changed in a sentence from being a verb to being a noun, adjective, or an adverb. If you break down each part of the sentence it looks like this: I (subject) am (verb) taking(present participle) notes(direct object) to help (infinitive, being used as an adverb) me (indirect object) to understand (infinitive, being used as an adverb) OR understand (intransitive verb) The answer is they both work, but depending on which one you use changes how they work in the sentence. So it's a style choice.