Learn Hardcore Turkish: Ders başlamadan önce hatırlatma yapmalıyım. - I must make a reminder before the lesson starts.

It means "I must make a reminder before class begins." The speaker is expressing that, before the class starts, they need to set or do a reminder.

How does the phrase başlamadan önce function to express time in the sentence?

The phrase is built from başlamak (to start) plus the negative participle suffix -madan, which means before starting. When combined with önce (meaning before), it clearly indicates that the action should occur prior to the beginning of the class.

What role does hatırlatma play in this sentence?

Hatırlatma is a noun meaning reminder. It is derived from the verb hatırlatmak (to remind) by adding the nominalizer -ma. In the sentence, it functions as the object of the verb phrase yapmalıyım, indicating what needs to be made or done.

How is obligation expressed in the verb yapmalıyım?

The verb yapmalıyım comes from yapmak (to do/make) with the addition of the obligation suffix -malı (or -meli) and the first-person singular ending -yım. This combination expresses necessity or duty, equivalent to saying "I must do/make" in English.