Learn Russian: Она беспокоится о том, что новое расписание непривычное. - She is worrying about the fact that the new schedule is unusual.

In Russian, prepositions like о (about) cannot attach directly to a conjunction like что (that). Instead, you use the pointer word то (that/the fact) as a bridge. You apply the preposition to то and follow it with что. Literally, this structure means "about the fact that".

Why is the pointer word то in the form том here?

The verb беспокоиться (to worry) requires the preposition о (about), which dictates the prepositional case. The prepositional case of the pronoun то is том.

Is there a connection between непривычное (unusual/unfamiliar) and the word for "habit"?

Yes! They share the same root. The word for habit is привычка, and the verb to get used to is привыкнуть. Adding the negative prefix не- and the neuter adjective ending -ое to match расписание gives you непривычное (something you are not used to).

Do I always need a comma before что in sentences like this?