La reunión continuó después.

Because reunión is a feminine noun, so it takes la.

A useful pattern is that many nouns ending in -ión are feminine:

• la reunión
• la canción
• la decisión

So the article has to agree with the noun’s gender.

Continuó is the third-person singular preterite of continuar.

That means it can mean:

• he continued
• she continued
• it continued

In this sentence, the subject is la reunión, so it means that the meeting continued.

The accent mark shows where the stress goes: con-ti-nu-Ó.

It is also important because it helps distinguish this form from other related forms:

• continúo = I continue
• continúa = he/she/it continues
• continuó = he/she/it continued

So the accent is not optional here; it is part of the correct spelling.

Spanish often uses the preterite when the speaker sees the action as a completed event or as a step in a sequence of events.

So La reunión continuó después presents continued as what happened next.

If you used continuaba, it would sound more like background information or an ongoing situation:

• La reunión continuaba después de la pausa.

So in this sentence, the preterite fits the idea of then the meeting continued.

Here después means afterwards, later, or then.

In this sentence, it works as an adverb on its own:

• La reunión continuó después.

But después can also be followed by de when you say what something is after:

• después de la pausa
• después de comer

So:

• después = afterwards / later
• después de + noun/infinitive = after

Yes. That is completely natural.

Both are correct:

• La reunión continuó después.
• Después, la reunión continuó.

The difference is mainly one of focus and word order:

• La reunión continuó después keeps the focus first on the meeting
• Después, la reunión continuó puts the time idea first: afterwards

Spanish is often flexible with this kind of adverb placement.

Very often, yes.

It can be used:

• intransitively: La reunión continuó.
• transitively: Continuaron la reunión.

So it can mean either:

• something continues
• someone continues something

In your sentence, it is intransitive because the meeting itself is the subject.

A simple pronunciation guide is:

la reu-nión con-ti-nu-ó des-pués

Approximate English-style guide: lah ray-oo-NYON con-tee-noo-O des-PWES

A few key points:

• reunión is stressed on the last syllable: -nión
• continuó is stressed on the last syllable: -nuó
• después is stressed on -pués

Yes, in many contexts that would work.

For example:

• La reunión continuó después.
• La reunión continuó luego.

Both can mean the meeting continued afterwards/later.

That said, después is often the more straightforward and common choice for afterwards. In everyday Spanish, both are normal.

No. Spanish usually leaves out subject pronouns when the subject is already clear.

Here, la reunión is explicitly stated, so there is no need for a pronoun:

• La reunión continuó después.

In fact, adding a pronoun would sound unnecessary here. Spanish normally uses pronouns only for emphasis, contrast, or clarity.