Tráeme la libreta y déjame también el marcapáginas encima de la mesa, por favor.

Because in affirmative commands, Spanish attaches object pronouns to the end of the verb.

So:

• trae = bring
• me = to me / for me
• tráeme = bring me

And:

• deja = leave
• me = for me / to me
• déjame = leave me / leave for me

This is very normal in Spanish command forms.
Compare with the negative:

• Tráeme la libreta.
• No me traigas la libreta.

In negative commands, the pronoun goes before the verb instead.

The accent marks keep the original stress of the command when the pronoun is attached.

Without the pronoun:

• trae
• deja

When me is added, Spanish often needs a written accent so the stress stays where it should be:

• tráeme
• déjame

So the accent is not random; it is there to show the correct pronunciation and stress.

Here me is an indirect object pronoun, meaning to me or for me.

So:

• Tráeme la libreta = bring the notebook to me
• Déjame el marcapáginas = leave the bookmark for me

English does not always say to me or for me explicitly, but Spanish often does.

This is the informal singular command form, used with tú.

The base commands here are:

• trae from traer
• deja from dejar

So the speaker is talking to one person informally.

If you wanted the formal singular form (usted), you would say:

• Tráigame la libreta...
• Déjeme también el marcapáginas...

If you were speaking to more than one person in Spain informally (vosotros), you would say:

• Traedme la libreta...
• Dejadme también el marcapáginas...

Spanish often uses the definite article (el, la, los, las) where English might prefer my, your, the, depending on context.

So la libreta does not necessarily mean only the notebook in a very abstract sense. In context, it can easily mean the notebook we both know about, or even my/your notebook, if that is already obvious.

If the speaker wanted to emphasize ownership, they could say:

• mi libreta
• tu libreta

But in everyday Spanish, the article is often enough.

Here el marcapáginas is singular.

This can be confusing because many English speakers expect a word ending in -s to be plural. But marcapáginas is a compound noun, and its singular and plural forms are often the same in Spanish.

So:

• el marcapáginas = the bookmark
• los marcapáginas = the bookmarks

The article tells you whether it is singular or plural.

It is also masculine, which is why it uses el.

No, not in this sentence.

Dejar can mean different things depending on the structure:

• Déjame ver. = let me see
• Déjame el marcapáginas. = leave me the bookmark / leave the bookmark for me

So here déjame does not mean let me. It means something like leave for me or leave with me, depending on context.

También means also or too.

In this sentence, it adds a second item to the request:

• bring me the notebook
• and also leave me the bookmark on the table

Its placement is fairly natural here, and it links el marcapáginas as an additional thing the speaker wants.

You could move it slightly, but the emphasis would change a bit:

• Déjame también el marcapáginas...
• Déjame el marcapáginas también...

Both are possible, but the original version sounds very natural.

Yes, sobre la mesa would also be possible.

Encima de la mesa means on top of the table and is very explicit about physical position.

Sobre la mesa also usually means on the table, and it can sound a little more neutral or slightly more formal depending on context.

A useful difference is that encima de strongly suggests resting on top of something, while sobre can sometimes be a bit broader.

Also, en la mesa is less precise, because it can mean on the table or at the table, depending on context. So encima de la mesa avoids ambiguity.

Because the speaker is making two connected requests in one sentence:

• Tráeme la libreta
• y déjame también el marcapáginas encima de la mesa

Using y sounds natural and efficient when you are asking for more than one action.

You could split it into two sentences:

• Tráeme la libreta. Déjame también el marcapáginas encima de la mesa, por favor.

That is also correct, but the original version sounds smoother as one combined request.

In a negative command, the pronoun goes before the verb, not attached to it.

So:

• Tráeme la libreta. → No me traigas la libreta.
• Déjame el marcapáginas. → No me dejes el marcapáginas.

This is one of the big differences between affirmative and negative commands in Spanish:

• affirmative: pronoun attached
• negative: pronoun before the verb

So a negative version of the whole sentence could be:

• No me traigas la libreta y no me dejes tampoco el marcapáginas encima de la mesa, por favor.