Learn Hardcore Portuguese (Portugal): Liga a coluna ao router por cabo e verifica se a ficha está bem colocada. - Connect the speaker to the router by cable and check if the plug is well inserted.

It’s the affirmative imperative for tu (informal “you”). From the present indicative tu ligas, the imperative drops the final -s: liga = “connect.”

How would I say this formally or to more than one person?

Formal/polite singular (você): Ligue a coluna ao router por cabo e verifique se a ficha está bem colocada.
Plural (vocês): Liguem … e verifiquem …

Why is there no subject pronoun like tu or você?

Portuguese normally drops subject pronouns because the verb ending already shows who is meant. Imperatives almost never include a subject pronoun.

Does ligar mean “to connect” or “to turn on”?

Both, depending on context:

Ligar X a Y = “to connect X to Y” (as here).
Ligar a luz = “to turn on the light.”
It can also mean “to phone”: ligar para alguém = “to call someone.”

Why is it ligar algo a algo and not another preposition?

The idiom is ligar [object] a [object] (“connect X to Y”). Hence a coluna ao router. Note the contraction a + o = ao. You wouldn’t use no (“in/on the”) here.

What does por cabo mean? Could I say com um cabo or via cabo?

Por cabo means “by cable” (i.e., a wired connection). Alternatives:

com um cabo = “with a cable”
via cabo = “via cable” All are fine in Portugal; por cabo is concise and common in instructions. You wouldn’t usually say por um cabo.

Does coluna really mean “speaker” and not just “column” or “spine”?

Yes. In European Portuguese, coluna (de som) is everyday for “speaker/loudspeaker.” A more technical or formal synonym is altifalante. Plural colunas often means a pair of speakers.

How do people in Portugal handle the word router?

They typically keep the English spelling router but pronounce it in a Portuguese way:

rúter [ˈʁu.tɨɾ] (very common)
ráuter [ˈʁaw.tɨɾ] (also heard) Brazilian roteador is not usual in Portugal.

Is verifica also an imperative?

Yes. It’s the tu affirmative imperative of verificar (“check/verify”): verifica = “check.”

What does se mean in verifica se…? Why is it está and not esteja?

Here se introduces an indirect question: “check if/whether…”. In this use, Portuguese takes the indicative: se a ficha está…. The subjunctive appears in conditional clauses: Se estiver mal colocada, … (“If it is wrongly inserted, …”).

What exactly is ficha? Is that the plug or the socket?

In European Portuguese:

a ficha = the plug (male end)
a tomada = the wall socket (female) Brazil often uses plugue for the plug.

Why is it bem colocada and not bem colocado?

Agreement. Ficha is feminine singular, so the participle-as-adjective agrees: colocada. The adverb bem (“well”) is invariable; don’t use bom here.

Could I say bem encaixada or bem ligada instead of bem colocada?

Yes:

bem encaixada emphasizes “snugly fitted/inserted.”
bem ligada emphasizes “properly connected.” All are natural in this context.

Can I move por cabo to another position?

Yes, but the given order is the most natural. Alternatives like Liga por cabo a coluna ao router or Liga a coluna, por cabo, ao router are possible but sound more marked/formal.

How would I replace a coluna with a pronoun (“connect it”)?

Use an enclitic pronoun with the affirmative imperative:

Feminine: Liga-a ao router.
Masculine: Liga-o ao router. Hyphen required after the verb.

What about the negative command forms and pronoun placement?

tu negative: Não ligues a coluna ao router…; Não a ligues ao router… (pronoun before the verb).
Formal singular: Não ligue…; plural: Não liguem…
In negatives, object pronouns go before the verb in European Portuguese.

Do I need the definite articles (a coluna, o router, a ficha)?

Yes, they’re natural here because the items are specific. Portuguese uses definite articles more than English in such instructions.

Do I need a comma before e (“and”)?

No. Liga … e verifica … doesn’t take a comma before e in standard punctuation.

Any quick pronunciation tips?

Approximate European Portuguese:

Liga [ˈliɣɐ]
coluna [kuˈlunɐ]
ao [aw]
router ≈ rúter [ˈʁu.tɨɾ] or ráuter [ˈʁaw.tɨɾ]
verifica [vɨˈɾifikɐ]
ficha [ˈfiʃɐ]
bem [bẽj]
colocada [kuluˈkadɐ]