Copriamo il parquet con il telo affinché non si rovini.

Grammatically, copriamo is the first person plural present of coprire.

So it can mean either:

• we cover
• let’s cover

Italian uses the same form for both meanings. The context tells you which one is intended.

In a practical situation like this, it often sounds like a suggestion or instruction, so let’s cover the parquet... is very natural. But in another context it could simply be a statement: we cover the parquet...

Italian normally uses the definite article much more often than English does.

So il parquet means the parquet floor or simply the wooden floor. Even when English might leave the article out in some contexts, Italian usually keeps it.

A few useful points:

• parquet is treated as a masculine singular noun
• it refers to parquet flooring / wooden flooring
• in this sentence it means the specific floor being talked about

So Copriamo il parquet is the normal way to say We are covering the parquet floor or Let’s cover the parquet floor.

Telo is a general word for a sheet, cloth, covering, or tarpaulin-like protective cover, depending on the situation.

Here, since the goal is to protect the floor, il telo most likely means something like:

• a protective sheet
• a drop cloth
• a covering sheet
• a tarp

So con il telo means with the sheet / with the protective cover.

The difference is the same basic one as the versus a/an in English.

• con il telo = with the sheet / the cover
  This suggests a specific sheet already known in the situation.
• con un telo = with a sheet / a cover
  This introduces it as any suitable sheet.

So the sentence uses il because the speaker probably has a particular cover in mind, or it is already understood from the context.

Affinché means so that or in order that.

It introduces a purpose clause: it explains why the floor is being covered.

So:

• Copriamo il parquet con il telo affinché non si rovini
• Let’s cover the parquet floor with the sheet so that it does not get damaged

A useful note: affinché is a bit more formal than some other options, especially in everyday speech.

They are very similar in this kind of sentence.

Both can mean so that / in order that:

• affinché non si rovini
• perché non si rovini

The main difference is style:

• affinché is usually more formal, more written, or more polished
• perché is often more common in everyday speech

So yes, in this sentence they are close in meaning, but affinché sounds a little more formal.

Because after affinché, Italian normally uses the subjunctive.

That is why you get:

• non si rovini = so that it does not get damaged

and not:

• non si rovina

Here is the contrast:

• si rovina = indicative, a statement of fact
• si rovini = subjunctive, used after a purpose expression like affinché

So rovini is the present subjunctive form.

Yes, si is part of the verb rovinarsi, which often means:

• to get damaged
• to get ruined
• to become spoiled

In English, we usually do not translate it as a truly reflexive action. The floor is not literally damaging itself in the usual sense. Instead, rovinarsi is a very natural Italian way to express that something ends up damaged.

So:

• non si rovini = so that it does not get damaged

A more explicitly passive version would be:

• affinché non venga rovinato

That also means so that it is not damaged, but non si rovini sounds very natural and common.

Because the purpose is negative: the speaker wants to prevent damage.

• affinché non si rovini = so that it does not get damaged

If you removed non, the meaning would become the opposite:

• affinché si rovini = so that it gets damaged

So non is essential here.

Yes. A native speaker might often choose a less formal version, such as:

• Copriamo il parquet con il telo perché non si rovini.
• Copriamo il parquet con un telo così non si rovina.

These are a bit more conversational.

The original sentence with affinché is correct and elegant, but in everyday spoken Italian many people would prefer perché or così.