A volte scelgo un libro a caso in libreria e poi lo leggo in giardino.

Yes. A volte means sometimes or at times.

• a = at
• volte = times

So literally it is something like at times, but in natural English we usually translate it as sometimes.

Examples:

• A volte cucino. = Sometimes I cook.
• A volte piove. = Sometimes it rains.

Italian often drops subject pronouns when they are not needed. The verb ending already shows who is doing the action.

• scelgo = I choose
• scegli = you choose
• sceglie = he/she chooses

Because scelgo already means I choose, adding io is optional. You would usually only include io for emphasis or contrast.

For example:

• Scelgo un libro. = I choose a book.
• Io scelgo un libro, tu scegli una rivista. = I choose a book, you choose a magazine.

Because scegliere is an irregular verb.

Its present tense forms are:

• io scelgo
• tu scegli
• lui/lei sceglie
• noi scegliamo
• voi scegliete
• loro scelgono

So scelgo is simply the correct I form of scegliere.

A caso means at random, randomly, or by chance, depending on context.

In this sentence, un libro a caso means a random book or a book at random.

It is a very common expression in Italian:

• aprire un libro a caso = to open a book at random
• scegliere qualcosa a caso = to choose something randomly

In Italian, a caso can come after the noun and sound very natural, especially in expressions like this.

So:

• scelgo un libro a caso = I choose a random book

You could also think of it as modifying the way the choosing happens, but in practice un libro a caso is a very normal chunk.

English and Italian place this kind of idea differently:

• English often says a random book
• Italian often says un libro a caso

No. This is a very important false friend.

• libreria = bookshop / bookstore
• biblioteca = library

So in libreria means in the bookshop or at the bookstore, not in the library.

Also, libreria can sometimes mean bookcase/bookshelf in other contexts, but in this sentence it clearly means bookshop.

Both are possible, but they mean slightly different things.

• in libreria often means at the bookshop / in a bookshop in a general sense
• nella libreria usually sounds more specific: in the bookstore or inside that particular bookstore

In your sentence, in libreria sounds natural because it describes the place where the action typically happens, without focusing on a specific shop.

Because the speaker is talking about a book, not a specific already-identified book.

• un libro = a book
• il libro = the book

Since the idea is choosing one random book, Italian uses the indefinite article un.

Lo is a direct object pronoun meaning it. It replaces un libro so you do not have to repeat the noun.

So:

• scelgo un libro
• poi lo leggo

Literally:

• I choose a book and then I read it

Because libro is masculine singular, the pronoun is lo.

Other direct object pronouns:

• la = it/her (feminine singular)
• li = them (masculine plural)
• le = them (feminine plural)

In Italian, direct object pronouns usually come before a conjugated verb.

So:

• lo leggo = I read it
• la vedo = I see her/it
• li compro = I buy them

This is different from English, where it comes after the verb: I read it.

With infinitives, pronouns can attach to the end:

• voglio leggerlo = I want to read it

But here leggo is a conjugated verb, so lo goes before it.

Poi means then, after that, or afterwards.

It connects the two actions in sequence:

1. I choose a book
2. then I read it

It is a very common word for narrating events:

• Studio e poi esco. = I study and then I go out.

Because in Italian, just like in English, the present tense can describe habitual actions.

So A volte scelgo... e poi lo leggo... means something like:

• Sometimes I choose... and then read it...

It does not have to mean the speaker is doing it right now. It can mean this is something they do from time to time.

Again, both can be possible, but the nuance is different.

• in giardino = in the garden, often in a general or usual-place sense
• nel giardino = in the garden, but more specifically in that particular garden

In your sentence, in giardino sounds natural because it is just naming the place where the speaker reads.

You will often see this kind of article omission in expressions of place:

• a scuola = at school
• in ufficio = in the office / at the office
• in giardino = in the garden

Yes, grammatically it could. But lo leggo is more natural because it avoids repeating libro.

Compare:

• Scelgo un libro a caso in libreria e poi leggo il libro.
• Scelgo un libro a caso in libreria e poi lo leggo.

The second version sounds smoother and more natural, just like English usually prefers I read it rather than repeating the book.

The given word order is very natural, but Italian allows some flexibility.

Standard version:

• A volte scelgo un libro a caso in libreria e poi lo leggo in giardino.

You could move some parts for emphasis, for example:

• A volte, in libreria, scelgo un libro a caso e poi lo leggo in giardino.
• A volte scelgo in libreria un libro a caso...

However, the original sentence is the most natural and neutral order for everyday Italian.

Yes, in the most direct reading, in libreria means the choosing happens in the bookshop.

So the sequence is:

• sometimes I choose a random book in the bookshop
• then I read it in the garden

Italian place phrases often sit near the part of the sentence they describe, and here in libreria naturally goes with scelgo.