Le défibrillateur est près de la trousse de secours.

In French, a singular countable noun usually needs an article or another determiner.

So:

• Le défibrillateur = the defibrillator
• not usually just défibrillateur on its own in a normal sentence

French uses articles more regularly than English. Omitting le here would sound incomplete unless it were a label, title, or sign.

Because the sentence uses le, which is the masculine singular definite article.

• le défibrillateur = masculine
• la trousse = feminine

There is no absolute rule for every noun, but many nouns ending in -ateur are masculine, and in this sentence the article confirms it clearly.

Près de means near or close to.

It is a fixed expression, so French uses:

• près de
  • noun

Examples:

• près de la porte = near the door
• près du bureau = near the desk
• près des escaliers = near the stairs

So in your sentence:

• Le défibrillateur est près de la trousse de secours.
• The defibrillator is near the first-aid kit.

Because près normally requires de before the following noun.

So you say:

• près de la trousse
• not près la trousse

This is just how the expression works in French.

Also, de combines differently depending on the article:

• près du = near the (masculine singular)
  (de + le = du)
• près de la = near the (feminine singular)
• près de l’ = near the (before vowel or mute h)
• près des = near the (plural)
  (de + les = des)

Because trousse is a feminine noun.

So:

• la trousse = the kit/case/pouch

In this sentence, trousse de secours is the standard way to say first-aid kit.

Because de secours is functioning like a descriptive phrase: a kit for emergency aid / first aid.

In many French noun phrases, de + noun is used without an article when the second noun expresses a type, function, or general category.

So:

• une trousse de secours = a first-aid kit
• une salle de classe = a classroom
• une bouteille d’eau = a bottle of water

Here, secours is being used in a general sense, not referring to specific the aid.

Est is the third-person singular form of être (to be).

• Le défibrillateur = subject
• est = is
• près de la trousse de secours = near the first-aid kit

So the structure is very similar to English:

• The defibrillator is near the first-aid kit.

French often uses être to describe location in simple sentences like this.

Not in the same way.

Your sentence names the object directly:

• Le défibrillateur est près de la trousse de secours.

That is the normal structure when the subject is already stated.

C’est is more often used for identification, presentation, or emphasis, for example:

• C’est le défibrillateur. = It’s the defibrillator.
• C’est près d’ici. = It’s near here.

So for this sentence, Le défibrillateur est... is the natural choice.

A careful pronunciation is roughly:

luh day-fee-bree-lah-tur eh pray duh lah trooss duh suh-koor

A more precise IPA version is:

/lə de.fi.bʁi.la.tœʁ ɛ pʁɛ də la tʁus də sə.kuʁ/

A few helpful notes:

• dé- sounds like day
• près sounds like preh/pray with an open e
• the French r is not like the English r
• the final s in près is silent
• secours ends with a pronounced r in standard French

The accents help show pronunciation.

• é usually sounds like ay
  So dé sounds like day
• è usually sounds more open, like eh
  So près has a more open vowel than pré would

Accents are important in French spelling and can sometimes change pronunciation or even meaning, so it is best to keep them when writing.