Learn Italian: C'è un dibattito stasera, ne parleremo domani. - There is a debate tonight, we will talk about it tomorrow.

In this sentence, ne replaces the phrase di questo dibattito (about this debate). Because the verb parlare requires the preposition di when you talk about something (parlare di), we use ne to avoid repeating the whole phrase.

Why couldn't we use a direct object pronoun like "lo" instead of "ne" to mean "it"?

If you used lo, it would imply you are talking it (as a direct object), rather than talking about it. Direct object pronouns like lo or la replace the direct target of a verb. Because we need to replace a phrase that starts with di (about), we must use the pronoun ne.

Where does "ne" go in the sentence compared to the verb?

Just like most other object pronouns in Italian (such as mi, ti, lo, la), the clitic pronoun ne is placed immediately before the conjugated verb, which in this case is parleremo.

Is the word "stasera" a combination of two words?