Escribe tu nombre en el lado izquierdo de la hoja.

Escribe here is the tú imperative of escribir, so it means Write!

• Escribes = you write / you are writing (normal present tense)
• Escribe = write! (command to one person, informal)
• Escriba = write! (command to one person, formal usted)

So the sentence is giving an instruction directly to one person in an informal way.

Because tu without an accent is the possessive adjective meaning your.

• tu = your
• tú = you

So:

• tu nombre = your name
• tú escribes = you write

This is a very common spelling distinction in Spanish.

In Spanish, possessives like mi, tu, su, nuestro usually go directly before the noun, without an article.

So you say:

• tu nombre = your name
• mi casa = my house
• su libro = his/her/your book

El tu nombre is not correct in standard Spanish for this kind of sentence.

Yes. Spanish often uses en where English uses in or on, depending on context.

Here, en el lado izquierdo de la hoja means on the left side of the sheet/page.

Spanish does not always match English prepositions exactly:

• en la mesa = on the table
• en la caja = in the box
• en la hoja = on the sheet/page

So en is the normal choice here.

Both kinds of expressions are possible, but they are slightly different in structure.

• el lado izquierdo de la hoja = the left side of the sheet
• la izquierda de la hoja is less natural in this exact context
• A more natural alternative would be en la parte izquierda de la hoja

So el lado izquierdo is a very clear, literal way to say the left side.

In Spanish, most adjectives usually come after the noun.

So:

• lado izquierdo = left side
• casa grande = big house
• libro interesante = interesting book

That is the normal adjective position in Spanish. Putting izquierdo before the noun would sound unnatural here.

De means of here, so:

• el lado izquierdo de la hoja = the left side of the sheet/page

This is a very common Spanish structure:

• la puerta de la casa = the door of the house
• el final del libro = the end of the book
• el nombre de la calle = the name of the street

So de la hoja tells you which left side: the left side of the sheet/page.

Spanish often uses the definite article more often than English does.

Here la hoja means the sheet/page, referring to the one already understood from the situation. For example, if someone gives you a worksheet or test paper, both speakers know which sheet is meant.

So de la hoja sounds natural because it refers to a specific sheet in context.

It can mean all three, depending on context.

Common meanings of hoja:

• leaf of a plant
• sheet of paper
• page of paper

In this sentence, it most likely means sheet of paper or page, depending on the situation.

That is why translations can vary slightly even when the Spanish stays the same.

Yes, very often.

• Escribe tu nombre = Write your name
• Pon tu nombre = literally Put your name, but in instructions it often means Write your name / Fill in your name

Both are common, especially on forms, worksheets, and classroom instructions. Escribe focuses more literally on writing; pon is a little broader and very natural in everyday instructions.

Usually it is omitted, because the verb form already shows who the command is for.

So the normal sentence is:

• Escribe tu nombre...

You could add tú only for emphasis or contrast, but it is not normally needed:

• Escribe tú tu nombre = You write your name (emphatic, contrastive)

That sounds marked, not neutral. In ordinary instructions, Spanish usually leaves the subject pronoun out.

Two useful points:

• The h is silent.
• The j has a strong throaty sound in Spain, similar to the ch in Scottish loch for many English speakers.

So hoja is pronounced roughly like OH-ha with a stronger, raspier h sound than in English.

Also:

• escribe = roughly es-KREE-be
• izquierdo = roughly ith-KYEHR-do in much of Spain, because z is often pronounced like th in thin

The exact pronunciation varies a little by region, but those are good Spain-Spanish approximations.