Ennen juhlia teetämme olohuoneeseen uudet verhot, jotta huone näyttää valoisammalta.

It means something different from plain we make.

• tehdä = to do, to make
• teettää = to have something done, to get something made

So:

• teemme uudet verhot = we make the new curtains
• teetämme uudet verhot = we have the new curtains made / we get the new curtains made

In this sentence, teetämme suggests that someone else will probably do the actual work for us, such as a professional sewer or shop.

Form breakdown:

• teetämme = 1st person plural present
• literally: we have made

So the sentence is not saying we ourselves sew the curtains, but rather we arrange for them to be made.

Because ennen normally takes the partitive.

So:

• ennen juhlia = before the party / before the celebration

Here juhlia is the partitive plural of juhlat.

A useful extra point: Finnish often uses juhlat in the plural when English would say party or celebration in the singular.

For example:

• syntymäpäiväjuhlat = birthday party
• häät = wedding
• juhlat = party / celebration

So even if English says before the party, Finnish naturally says ennen juhlia.

Because this is the illative case, which usually means into or to.

• olohuone = living room
• olohuoneessa = in the living room
• olohuoneeseen = into / to the living room

In this sentence, the idea is that the curtains are being made for that room, as something that will go there. Finnish often uses the illative in this kind of situation, where English might use for.

So:

• teetämme olohuoneeseen uudet verhot
  = we’re having new curtains made for the living room

Even though the literal case meaning is something like into the living room, the natural English translation is for the living room.

Because uudet verhot is a total object: it refers to the whole, complete set of curtains.

In other words, the sentence means that the speakers intend to have the new curtains made as a complete result.

• uudet verhot = the full set of new curtains
• uusia verhoja would sound more like some new curtains, new curtains in general, or an incomplete/ongoing amount

This is a very common Finnish contrast:

• Ostan kirjat. = I’ll buy the books / the whole set
• Ostan kirjoja. = I’m buying books / some books

Here the idea is clearly result-oriented and complete, so uudet verhot is the natural choice.

jotta means so that or in order that.

It introduces a purpose clause: it tells you the goal of the action.

So:

• jotta huone näyttää valoisammalta
  = so that the room looks brighter

The logic of the sentence is:

1. We have new curtains made.
2. The purpose is that the room will look brighter.

So jotta connects the action with its intended result.

Because with näyttää in the sense of to look / to seem, Finnish normally uses the adjective in the ablative form -lta / -ltä.

For example:

• näyttää hyvältä = looks good
• näyttää oudolta = looks strange
• näyttää valoisammalta = looks brighter

So:

• huone on valoisampi = the room is brighter
  
  • this sounds more like a factual statement
• huone näyttää valoisammalta = the room looks brighter
  
  • this focuses on appearance

That is why valoisammalta is the natural form after näyttää here.

It comes from the adjective valoisa = bright.

Step by step:

1. valoisa = bright
2. valoisampi = brighter
   
   • this is the comparative
3. valoisammalta = from the comparative + ablative ending
   
   • used after näyttää

So the pattern is:

• adjective: valoisa
• comparative: valoisampi
• after näyttää: valoisammalta

The double mm is normal when the comparative stem takes a case ending:

• suurempi → suuremmalta
• kauniimpi → kauniimmalta
• valoisampi → valoisammalta

The verb forms are present tense:

• teetämme
• näyttää

But in Finnish, the present tense is very often used for the future when the context makes the time clear.

Here the future meaning comes from ennen juhlia = before the party.

So the sentence is grammatically in the present, but the meaning is naturally future-oriented:

• Before the party, we’ll have new curtains made...

This is very normal Finnish usage.

Yes, Finnish word order is fairly flexible, although some orders sound more natural than others.

This sentence starts with Ennen juhlia because putting the time expression first is very natural. It sets the scene right away:

• Ennen juhlia teetämme olohuoneeseen uudet verhot...

You could rearrange parts of the sentence, and it would still be understandable, for example:

• Teetämme ennen juhlia olohuoneeseen uudet verhot...

But the original version is smooth and neutral, especially in written Finnish.

So the word order is not random, but it is also not as fixed as in English.