Jo porto una tovallola gran, un barret i unes ulleres a la motxilla.

Yes — Catalan usually does drop subject pronouns because the verb ending already shows who is doing the action.

So Porto una tovallola gran... is completely natural.

Adding jo gives a bit more emphasis or contrast, for example:

• Jo porto una tovallola, però ell no.
• I am carrying a towel, but he isn’t.

In a simple neutral sentence, both versions work, but without jo is often more typical.

Porto is the 1st person singular present tense of portar.

• portar = to carry / to bring / to wear
• porto = I carry / I’m carrying / I wear / I bring

Catalan portar is broader than English carry. Depending on context, it can mean:

• carrying something with you
• wearing something
• bringing something somewhere

In this sentence, it means I’m carrying / I have with me.

Because the article has to agree with the noun in gender and number.

• tovallola is feminine singular → una tovallola
• barret is masculine singular → un barret
• ulleres is feminine plural → unes ulleres

So the articles are matching each noun correctly.

Normally, ulleres is used in the plural, just like English glasses.

So:

• unes ulleres = a pair of glasses

The singular ullera exists, but it usually does not mean an ordinary pair of glasses. It can refer to one lens, an eyepiece, or something more specialized depending on context.

For everyday eyewear, learners should think of ulleres as a plural noun.

In Catalan, adjectives often come after the noun.

So:

• una tovallola gran = a big towel

This is more normal in Catalan than putting the adjective before the noun.

English often says:

• a big towel

Catalan often says:

• una tovallola gran

That’s a very common word order pattern.

Yes. In this sentence, gran means big or large.

With objects, gran very often refers to size:

• una casa gran = a big house
• una tovallola gran = a big towel

With people or abstract ideas, gran can sometimes mean things like grown-up, older, or great, but here it is simply about physical size.

A la is:

• a = to / at / in (depending on context)
• la = the feminine singular article

So a la motxilla literally contains a + la.

Because motxilla is a feminine noun, you use la, not el.

Compare:

• a la motxilla = in the backpack
• al cotxe = in/to the car
  (a + el = al)

So a la is not a special single word here — it is just the preposition plus the feminine article.

This is one of those places where Catalan and English don’t match word-for-word.

In Catalan, a la motxilla is natural for the idea of having something in the backpack. English would normally use in, but Catalan can use a in this kind of expression.

If you want to be extra explicit about inside, Catalan can also say:

• dins la motxilla
• dins de la motxilla

But a la motxilla is a normal, idiomatic way to express it.

So learners should not read it too literally as to the backpack.

Normally, it is understood as applying to the whole list:

• the towel
• the hat
• the glasses

So the idea is that all of those things are in the backpack.

Because the phrase comes at the end, a learner might briefly wonder whether it attaches only to the last noun, but in normal reading it usually describes the overall situation: these are the things the speaker has in the backpack.

If someone wanted to make that especially clear, they could also say:

• A la motxilla porto una tovallola gran, un barret i unes ulleres.

The word order is not completely fixed. Catalan allows some flexibility.

These are all possible, with slightly different emphasis:

• Jo porto una tovallola gran, un barret i unes ulleres a la motxilla.
• Porto una tovallola gran, un barret i unes ulleres a la motxilla.
• A la motxilla porto una tovallola gran, un barret i unes ulleres.

Putting a la motxilla first gives more focus to the location.

So yes, you can move it, as long as the sentence stays clear and natural.

This works much like standard English list punctuation.

In a simple list, Catalan normally uses:

• commas between earlier items
• i before the final item
• usually no comma before i

So:

• una tovallola gran, un barret i unes ulleres

That is the normal way to write a three-item list in Catalan.