Cuando entro en casa, procuro no pisar la alfombra con las botas sucias.

Because the sentence describes a habit or something that usually happens.

• Cuando entro en casa... means When / Whenever I come into the house...
• In Spanish, the present tense is very commonly used for repeated or habitual actions.

If you said Cuando entre en casa..., that would usually refer to a future occasion:

• Cuando entre en casa, me quitaré las botas. = When I come into the house, I’ll take off my boots.

So here, entro fits the idea of a general routine.

In Spain, entrar en is the most standard and natural pattern.

• entrar en casa = to go into / enter the house
• entrar a casa can be heard in some varieties of Spanish, especially in parts of Latin America, but it is less standard in Spain.

So for Peninsular Spanish, entro en casa is the safest choice.

Because entrar already expresses movement into a place, and Spanish normally uses en with entrar.

• entrar en casa = to enter the house / go into the house

By contrast, a casa is common with verbs of movement like:

• voy a casa = I’m going home
• vuelvo a casa = I return home

So:

• entro en casa ✅
• voy a casa ✅

They use different prepositions because the verbs work differently.

Procurar here means to try, to make an effort, or to make a point of doing something.

• Procuro no pisar... = I try not to step on... / I make a point of not stepping on...

Compared with intentar, procurar can sound a bit more like a careful habit or conscious effort, which fits this sentence well.

• Intento no pisar la alfombra... is also possible.
• Procuro no pisar la alfombra... sounds slightly more natural for a regular precaution or good habit.

Because after procurar, Spanish uses an infinitive.

• procuro pisar
• procuro no pisar

This is the same pattern as:

• quiero salir = I want to leave
• intento dormir = I try to sleep
• prefiero esperar = I prefer to wait

So pisar stays in the infinitive because it depends on procuro.

Because no negates the infinitive phrase.

• procuro no pisar la alfombra = I try not to step on the carpet

The negative belongs to pisar, not to procuro.

Compare:

• Procuro no llegar tarde. = I try not to arrive late.
• No procuro llegar tarde. = I do not try to arrive late.
  This is grammatically possible, but it means something different and sounds less natural in most situations.

So in your sentence, no goes right before the infinitive because the idea is not stepping on the carpet.

Pisar literally means to step on or to tread on.

In this sentence:

• pisar la alfombra = to step on the carpet

It is a very natural verb when talking about your feet touching a surface.

It is more specific than a general verb like caminar (to walk).
You are not just walking; you are specifically putting your boots onto the carpet.

Because Spanish usually uses the definite article with specific, known things.

• la alfombra = the carpet / the rug

In a house, if both speaker and listener understand which carpet is meant, Spanish naturally uses la.

Dropping the article would sound unnatural here.

Spanish often uses the definite article instead of a possessive adjective when the owner is obvious.

So:

• con las botas sucias literally = with the dirty boots
• but naturally it means with my dirty boots, because they are obviously the speaker’s boots

This is very common in Spanish, especially with clothing, body parts, and personal items.

Compare:

• Me lavo las manos. = I wash my hands.
• Se quitó la chaqueta. = He took off his jacket.

You can say mis botas sucias if you want to emphasise that they are my boots, but it is not necessary here.

It means the boots are dirty.

In con las botas sucias, the adjective sucias agrees with botas:

• botas = feminine plural
• sucias = feminine plural

So grammatically, sucias clearly describes botas, not alfombra.

If you wanted to describe the carpet as dirty, you would say something like:

• la alfombra sucia

Yes, you could, but the feel is slightly different.

• Cuando entro en casa, procuro no pisar la alfombra...
  = When / Whenever I come into the house, I try not to step on the carpet...
• Al entrar en casa, procuro no pisar la alfombra...
  = On entering the house / When entering the house, I try not to step on the carpet...

Both are correct.
Cuando entro sounds a bit more like a repeated personal routine.
Al entrar sounds a bit more compact and slightly more formal or written.

It can correspond to either house or home in English, depending on context.

In Spanish, casa is very commonly used where English would often prefer home:

• entro en casa = I come into the house / I come home and go inside

So even though the literal word is house, the feeling is often closer to home in everyday use.

Yes. It is a very natural structure for describing a repeated action or habit:

• Cuando + present tense for a regular situation
• main verb in the present tense
• infinitive after verbs like procurar

Pattern:

• Cuando llego a casa, procuro hablar bajo.
• Cuando salgo, intento no hacer ruido.

So your sentence is a good model for talking about things you usually try to do or avoid doing.