Mia nova horaro estas en la kalendaro sur la muro.

Because they are both adjective-like words modifying horaro.

• mia = my
• nova = new
• horaro = schedule / timetable

In Esperanto, adjectives end in -a, and possessive words like mia, via, lia, etc. also behave like adjectives.

They match the noun they describe in number and case. Here horaro is singular and not accusative, so both stay in the basic -a form:

• mia nova horaro = my new schedule

If the noun were plural, they would also become plural:

• miaj novaj horaroj = my new schedules

Horaro means something like schedule, timetable, or list of times.

It is built from:

• horo = hour
• -ar- = a suffix meaning a collection or group of things
• -o = noun ending

So horaro is literally something like a collection of hours / times, which naturally becomes schedule or timetable.

This suffix appears in other words too:

• arbo = tree → arbaro = forest
• vorto = word → vortaro = dictionary, vocabulary list

This is a very common thing English speakers notice.

Esperanto uses en where English often uses either in or on, depending on the idea. With kalendaro, en la kalendaro is natural because something is thought of as being inside the calendar as an entry.

So:

• en la kalendaro = literally in the calendar
• but in natural English, the meaning may be on the calendar

This is a good reminder not to translate prepositions word-for-word from English.

Because sur means on, on top of, or on the surface of.

A calendar is attached to the surface of a wall, so:

• sur la muro = on the wall

If you said en la muro, that would mean in the wall, as if it were inside the wall itself.

So the sentence distinguishes two different relationships:

• the schedule is en la kalendaro
• the calendar is sur la muro

Normally it describes the calendar.

So the natural interpretation is:

• My new schedule is in the calendar [that is] on the wall.

In other words, the calendar is on the wall, and the schedule is in that calendar.

This is the most sensible reading because a calendar can easily be on the wall, while a schedule is not usually thought of that way in this sentence.

If someone wanted to make the structure even clearer, they could rephrase it, but as written, most readers will naturally connect sur la muro with la kalendaro.

La is the definite article, meaning the.

Esperanto has:

• la = the
• no indefinite article like a/an

Here la kalendaro suggests a specific calendar, probably one that both speaker and listener can identify. Likewise, la muro means a specific wall.

So:

• en la kalendaro = in the calendar
• sur la muro = on the wall

Very often, if something is clearly identifiable from the situation, la is used.

Because there is no direct object here.

The sentence is:

• Mia nova horaro = the subject
• estas = is
• en la kalendaro sur la muro = a prepositional phrase describing location

In Esperanto, the accusative -n is usually used for:

1. a direct object
2. motion toward something in certain expressions

Neither is happening here.

This sentence describes a location, not movement. So we use:

• en la kalendaro = in the calendar
• sur la muro = on the wall

If movement were involved, you might see -n:

• Mi metas la kalendaron sur la muron. = I put the calendar onto the wall.

There, sur la muron shows movement onto the wall.

Yes. Esperanto word order is fairly flexible, although some orders sound more neutral than others.

The given sentence:

• Mia nova horaro estas en la kalendaro sur la muro.

is a normal, neutral way to say it.

You could also say:

• En la kalendaro sur la muro estas mia nova horaro.

That puts more focus on the location first.

Even though word order can move around, the original version is probably the easiest and most natural for a learner.

In a full sentence like this, yes.

Estas is the verb is. It links the subject with the location:

• Mia nova horaro estas en la kalendaro...
• My new schedule is in the calendar...

Without estas, it would not be a complete normal sentence.

Esperanto usually keeps this linking verb where English would also use is/are.

Yes. Horaro can mean several related things, depending on context:

• schedule
• timetable
• program of times

The exact English translation depends on what kind of thing is being talked about:

• school timetable
• work schedule
• train timetable
• event schedule

So the Esperanto word is broad, and context tells you the best English choice.