Sin el primer párrafo, este texto no tiene sentido.

Primer is a shortened form of primero that is used before a singular masculine noun.

• el primer párrafo = the first paragraph
• el primero = the first one

So here, because it comes directly before the masculine singular noun párrafo, Spanish uses primer.

Examples:

• el primer día
• el primer libro
• but el día primero is a different, more formal/literary pattern in some contexts.

Because the sentence is talking about a specific paragraph: the first paragraph.

• sin el primer párrafo = without the first paragraph
• sin un párrafo = without a paragraph
• sin párrafo would sound unnatural here

Spanish often uses the definite article where English does too, especially when referring to something clearly identified.

Sin means without.

It is a preposition, so it is followed by a noun phrase:

• sin el primer párrafo = without the first paragraph
• sin azúcar = without sugar
• sin problema = without a problem / no problem

So the opening part sets up the condition: if you remove the first paragraph, the text no longer makes sense.

The comma is used because Sin el primer párrafo has been moved to the front of the sentence for emphasis or clarity.

Basic order:

• Este texto no tiene sentido sin el primer párrafo.

Fronted version:

• Sin el primer párrafo, este texto no tiene sentido.

Both are natural. The version with the comma highlights the condition first: Without the first paragraph...

Because tener sentido is the normal Spanish expression for to make sense / to have meaning.

Literally:

• tener = to have
• sentido = sense

So:

• tiene sentido = it makes sense
• no tiene sentido = it doesn’t make sense

This is one of those cases where Spanish and English use different verb structures.

Because the subject is este texto, which is singular.

• este texto = singular
• so the verb is tiene

If it were plural, the verb would change:

• Estos textos no tienen sentido.

So the structure is:

• este texto = subject
• no tiene = verb phrase
• sentido = noun/complement

Spanish demonstratives depend on how the speaker is mentally pointing to something.

• este texto = this text (closer to the speaker, or the one currently being discussed)
• ese texto = that text (a bit more distant)
• esto = this as a pronoun, not used before a noun

Because texto is a noun, you need este, not esto.

So:

• este texto = correct
• esto texto = incorrect

Here sentido means sense, in the idea of meaning, logic, or coherence.

So no tiene sentido can mean:

• it doesn’t make sense
• it has no meaning
• it is not logical

In this sentence, it probably means the text becomes unclear or incoherent if the first paragraph is missing.

Because Spanish often omits subject pronouns when the subject is already clear.

In English, you need:

• It doesn’t make sense

In Spanish, the subject can be stated as a noun instead:

• Este texto no tiene sentido

Or, if the context is clear, Spanish might even omit the noun:

• No tiene sentido

The verb form tiene already tells you it is third person singular.

Because the stress falls on the first syllable: PÁ-rra-fo.

Without the accent, Spanish stress rules would suggest a different pronunciation. The written accent shows that the stress does not follow the default pattern.

So:

• párrafo = stress on pá

This is useful both for pronunciation and spelling.

Yes. A very natural alternative is:

• Este texto no tiene sentido sin el primer párrafo.

This means the same thing. The difference is mainly emphasis:

• Sin el primer párrafo, este texto no tiene sentido.
  Emphasises the missing paragraph first.

• Este texto no tiene sentido sin el primer párrafo.
  Starts with the main subject, this text.

Both are correct and natural.

No, but it is the most common and neutral way.

Other possibilities include:

• Este texto carece de sentido sin el primer párrafo.
  = This text lacks sense/meaning without the first paragraph.
  More formal.

• Sin el primer párrafo, este texto no se entiende.
  = Without the first paragraph, this text can’t be understood.
  Focuses more on comprehension.

But no tiene sentido is the everyday expression a learner should know best.