Desde que montamos el trípode, la montura no se mueve.

Because desde on its own is usually followed by a noun or time expression, such as desde ayer or desde Madrid.

When it is followed by a whole clause with a verb, Spanish normally uses desde que:

• desde ayer = since yesterday
• desde que llegamos = since we arrived

In this sentence, montamos el trípode is a full clause, so desde que is the natural choice.

Here montamos is understood as the preterite: we set up / we assembled.

A useful thing to know is that montamos can mean two different things depending on context:

• present: we set up / we assemble
• preterite: we set up / we assembled

The form is identical. In this sentence, desde que makes the past reading much more likely:

• Desde que montamos el trípode... = Since we set up the tripod...

So the action of setting it up is treated as a completed event in the past, and the result continues into the present.

Because Spanish usually doesn’t need subject pronouns unless they are needed for emphasis, contrast, or clarity.

The verb ending -amos already tells you the subject is we.

So:

• montamos el trípode = we set up the tripod

You could say nosotros montamos el trípode, but it would sound more emphatic, like we set it up.

Because moverse means to move in the sense of to shift / to move itself / to be moving.

Compare:

• mover algo = to move something
  
  • Muevo la mesa. = I move the table.
• moverse = to move
  
  • La mesa se mueve. = The table moves / is moving.

So:

• la montura no se mueve = the mount doesn’t move

Without se, la montura no mueve would sound incomplete, because it would suggest the mount does not move something.

Because the sentence is describing a current ongoing situation that started in the past and is still true now.

• Desde que montamos el trípode = since we set up the tripod
• la montura no se mueve = the mount doesn’t move / isn’t moving

Spanish often uses the present tense for something that began earlier and still holds true now.

In English, you might also say:

• the mount hasn’t moved
• the mount doesn’t move

Spanish could also say no se ha movido, but no se mueve focuses more on the present state: it is stable now.

Grammatically, yes, the form itself is ambiguous. But in this sentence, the context strongly points to the past meaning.

Desde que usually introduces the moment from which something has been true:

• Desde que llegamos, todo va bien. = Since we arrived, everything has been going well.

So Desde que montamos el trípode is naturally understood as Since we set up the tripod.

Montura has several meanings depending on context, such as:

• frame (of glasses)
• mount (for equipment)
• saddle
• mounting / support structure

In this sentence, because of trípode, it most likely means the mount or the mounting head/support attached to the tripod.

So the idea is that once the tripod was set up, the attached support or mount became stable.

They are not the same thing.

• el trípode = the tripod itself, the three-legged stand
• la montura = the mount/head/support attached to it, or the part holding the device

So the sentence suggests something like:

• we set up the tripod
• as a result, the mount is now stable and doesn’t move

This distinction is common in photography, video, telescopes, and similar equipment.

Because trípode is stressed on the first syllable: TRÍ-po-de.

Spanish spelling rules say that words stressed on the third-to-last syllable (esdrújulas) always take a written accent.

So:

• trípode → accent required

This accent mark is purely about stress/pronunciation, not grammar.

It is very natural here, because Desde que montamos el trípode is an introductory subordinate clause.

So this is a normal written pattern:

• Desde que montamos el trípode, la montura no se mueve.

The comma helps separate the background information from the main clause.

In very informal writing, some people may omit it, but using the comma here is standard and clear.

Yes. Spanish word order is flexible.

For example:

• La montura no se mueve desde que montamos el trípode.

This means essentially the same thing.

The version with Desde que... first gives more emphasis to the time/background condition.
The version starting with La montura no se mueve... puts the main point first.

Both are correct.

Because nouns in Spanish have grammatical gender.

• el trípode is masculine
• la montura is feminine

This affects the article:

• el for masculine singular nouns
• la for feminine singular nouns

There is no special reason in this sentence beyond learning each noun with its article.

You could, but it would not be the most natural choice in many contexts.

Spanish often prefers the simple past (preterite) after desde que when referring to the starting event:

• Desde que montamos el trípode...

Using hemos montado is grammatically possible in some varieties or contexts, but it can sound less straightforward here. In standard everyday usage, especially with a clearly completed event that serves as a starting point, montamos is very natural.

Yes. The Spanish present tense often covers both ideas.

So la montura no se mueve can mean:

• the mount doesn’t move (general/current state)
• the mount isn’t moving (right now)

In this sentence, the broader idea is probably it is stable / it doesn’t budge.

Very often, yes, but not always in exactly the same way in English.

Here it means since in the time sense:

• Desde que montamos el trípode... = Since we set up the tripod...

But when translating, English may choose different wording depending on style:

• Since we set up the tripod, the mount doesn’t move.
• Ever since we set up the tripod, the mount hasn’t moved.
• After we set up the tripod, the mount stopped moving.

So desde que is usually since, but the best English translation can vary a little depending on nuance.

Yes, very much so.

Montar is a very useful verb in Spanish and can mean things like:

• to assemble
• to put together
• to set up
• to mount

With equipment, furniture, stands, and similar objects, montar is very common:

• montar un trípode = set up a tripod
• montar una tienda de campaña = put up a tent
• montar un mueble = assemble a piece of furniture

So in this sentence, montamos el trípode sounds natural and idiomatic.