אנחנו משלמים את המקדמה לפני ההריסה.

A natural pronunciation is:

anachnu meshalmim et hamikdama lifnei haharisa

Approximate stress:

• aNACHnu
• meshalMIM
• et
• hamikdaMA
• lifNEI
• hahariSA

A very rough English-style guide would be:

ah-NAKH-noo मेh-shahl-MEEM et hah-meek-dah-MAH leef-NAY hah-hah-ree-SAH

Because Hebrew normally does not use a present-tense form of to be the way English does.

So:

• אנחנו משלמים can mean we pay
• or we are paying

The word משלמים itself carries the present-time idea. Hebrew does not need a separate word for are here.

Hebrew present-tense verbs agree with the subject in gender and number.

Here the subject is אנחנו = we, so the verb is plural.

• משלמים = masculine plural
• משלמות = feminine plural

So:

• a mixed group or a group of men would usually say אנחנו משלמים
• a group of women can say אנחנו משלמות

Masculine plural is also the default form in many situations.

משלמים is the present tense, masculine plural form of לשלם = to pay.

Useful related forms:

• משלם = he pays / is paying
• משלמת = she pays / is paying
• משלמים = they pay / are paying, or we if masculine/mixed
• משלמות = they pay / are paying, or we if feminine

The verb comes from the root ש-ל-ם.

את marks a definite direct object.

In this sentence, המקדמה means the advance payment / the deposit / the down payment, which is definite because it has ה־ = the.

So Hebrew uses:

• את המקדמה

But if the object were indefinite, you would usually not use את:

• אנחנו משלמים מקדמה = we pay an advance payment / a deposit

Important: את usually does not get translated into English. It is a grammar marker.

המקדמה is:

• ה־ = the
• מקדמה = advance payment / down payment / deposit

It is a feminine singular noun.

So:

• מקדמה = an advance payment
• המקדמה = the advance payment

לפני is a preposition meaning before.

After לפני, you simply put the noun phrase:

• לפני הריסה = before a demolition / before demolition
• לפני ההריסה = before the demolition

Since הריסה is definite here, it takes ה־.

Also, לפני is a separate word, so the article stays on the noun:

• לפני ההריסה

ההריסה means the demolition.

It is a noun built from the verb להרוס = to demolish / to destroy.

So:

• הריסה = demolition
• ההריסה = the demolition

It is a feminine singular noun.

In other contexts, הריסה can also mean destruction, depending on what is being talked about.

Grammatically, it is present tense:

• אנחנו משלמים = we pay / we are paying

However, in real Hebrew, present tense can sometimes describe a planned or scheduled future action, depending on context.

If you wanted an explicitly future form, you would usually say:

• אנחנו נשלם את המקדמה לפני ההריסה = we will pay the advance payment before the demolition

Yes. The basic word order here is very natural:

• אנחנו משלמים את המקדמה לפני ההריסה

But Hebrew allows changes for emphasis or style. For example:

• לפני ההריסה אנחנו משלמים את המקדמה
  Emphasizes before the demolition

• את המקדמה אנחנו משלמים לפני ההריסה
  Emphasizes the advance payment

The original sentence is the most neutral and straightforward version.

Yes, but that would be a different structure.

Your sentence uses a noun:

• לפני ההריסה = before the demolition

If you wanted a clause with a verb, Hebrew might use something like:

• לפני שאנחנו הורסים
• לפני שיהרסו
• לפני שמבצעים את ההריסה

So the sentence you have is using the compact noun-based structure before the demolition, not a full clause like before we demolish.