La mesa nueva encaja mejor junto a la ventana, aunque todavía no sabemos dónde poner la lámpara.

Both are possible, but they can sound slightly different.

• la mesa nueva is the more neutral, everyday order: noun + adjective
• la nueva mesa can sound a bit more expressive or contrastive, like the new table as opposed to the old one

In this sentence, la mesa nueva simply describes the table as new, without extra emphasis.

Here, encaja means something like:

• fits
• works well
• goes well
• suits the space

So La mesa nueva encaja mejor junto a la ventana means the new table fits or works better next to the window.

The verb is encajar, and encaja is the third-person singular present form:

• la mesa encaja = the table fits

Mejor is the correct comparative form here: better.

• bien = well
• mejor = better

Spanish does not say más mejor. That would be like saying more better in English.

Also, más bien usually means something different, often closer to:

• rather
• more like
• actually

So in this sentence:

• encaja mejor = fits better

Junto a means:

• next to
• beside
• by

So:

• junto a la ventana = next to the window

You could also hear:

• al lado de la ventana = next to / beside the window
• cerca de la ventana = near the window

But junto a usually suggests being quite close, often right beside something.

Because ventana is a feminine noun:

• la ventana

The contraction al only happens with:

• a + el = al

It does not happen with feminine articles.

So:

• junto a la ventana = correct
• junto al ventana = incorrect

Aunque means although / even though, and it introduces a subordinate clause.

• ..., aunque todavía no sabemos... = ..., although we still don’t know...

You could think of the sentence structure as:

• The table fits better by the window,
• although we still don’t know where to put the lamp.

Pero means but, and it links ideas more directly:

• ..., pero todavía no sabemos...

That would also be possible in some contexts, but aunque sounds more like a concession: one thing is true despite the other.

In Spanish, no normally goes before the conjugated verb:

• no sabemos = we don’t know

Todavía means still or yet, depending on context.

So:

• todavía no sabemos = we still don’t know / we don’t know yet

Word by word:

• todavía = still / yet
• no = not
• sabemos = we know

Yes. In this sentence, todavía and aún are both possible:

• aunque todavía no sabemos...
• aunque aún no sabemos...

Both mean:

• although we still don’t know...
• although we don’t know yet...

In everyday speech, todavía is often very common and clear for learners.

Because it is an interrogative word used in an indirect question.

Compare:

• No sabemos dónde poner la lámpara.
  = We don’t know where to put the lamp.

Here, dónde means where, and it keeps the accent because it introduces a question indirectly.

Without the accent, donde is usually a relative word:

• El lugar donde la pusimos = The place where we put it

So:

• dónde = where? / in indirect questions
• donde = where as a relative word

Because after verbs like saber, Spanish often uses an indirect question + infinitive when the subject is the same.

• No sabemos dónde poner la lámpara
  = We don’t know where to put the lamp

This is very natural because we are the ones who would put it.

You could also say:

• No sabemos dónde ponerla = We don’t know where to put it

Using a full clause like dónde la ponemos is possible in some contexts, but the infinitive structure is very common and elegant after saber, decidir, pensar, etc.

Because la lámpara is the direct object of poner:

• poner la lámpara = to put the lamp

In Spanish, infinitives often keep their object right after them:

• comprar el libro = to buy the book
• abrir la puerta = to open the door

You could also replace it with a pronoun:

• dónde ponerla = where to put it

Sabemos is the present tense of saber:

• yo sé
• tú sabes
• él/ella sabe
• nosotros sabemos

It is used because the sentence is talking about the current situation:

• right now, the table fits better by the window
• right now, we still don’t know where to put the lamp

So the present tense matches the idea of a present discussion or decision.

Yes, it can be very natural.

Encajar is often used when something:

• physically fits
• suits a space
• works well in a layout
• matches overall arrangement

With furniture, it can mean:

• This table fits here
• That chair doesn’t really work in that corner

So in this sentence, encaja mejor suggests that the table is better placed or better suited next to the window.

Yes, that is also correct.

These are both natural:

• todavía no sabemos dónde poner la lámpara
• no sabemos todavía dónde poner la lámpara

The first one often sounds slightly more common and flowing in conversation, but both are fine.

The meaning stays the same:

• we still don’t know where to put the lamp

In most of Spain:

• ll in lámpara is not relevant, but if it appeared, many speakers pronounce ll and y similarly
• z in ventana is not there, but if you had a word like luz, the z would usually sound like the th in think
• c before e/i also often has that th sound in Spain

In this sentence, one useful pronunciation point is dónde:

• stress falls on the first syllable: DÓN-de

And encaja in many parts of Spain sounds roughly like:

• en-KA-ha because the j is a throaty sound, not an English j

A quick breakdown:

• La mesa nueva = subject noun phrase
• encaja mejor = verb + comparative adverb
• junto a la ventana = place expression
• aunque = linking word meaning although
• todavía no sabemos = main verb of the second clause
• dónde poner la lámpara = indirect question with infinitive

So the sentence is basically:

1. The new table fits better next to the window
2. although we still don’t know where to put the lamp