Se la rezultoj estos bonaj, nia instruistino donos al ni novan temon poste.

Esperanto does not follow the English rule that avoids will after if.

In Esperanto, you normally use the tense that matches the actual time of the action. Since the results are in the future, estos is natural:

• Se la rezultoj estos bonaj... = if the results will be / turn out to be good

So using the future in both parts of the sentence is completely normal:

• estos = will be
• donos = will give

Because rezultoj is plural, and adjectives in Esperanto must agree with the nouns they describe.

• rezulto = result
• rezultoj = results

And:

• bona = good
• bonaj = good, describing a plural noun

So:

• la rezultoj estos bonaj = the results will be good

The -j marks plural on both the noun and the adjective.

Because rezultoj is the subject of estos, not a direct object.

In this clause:

• la rezultoj = the results
• estos = will be
• bonaj = good

The results are the thing that will be good, so they are the subject. Subjects do not take -n.

Compare:

• La rezultoj estos bonaj. = The results will be good.
• Mi vidas la rezultojn. = I see the results.

In the second sentence, rezultojn gets -n because it is a direct object.

Instruistino means female teacher.

It is built like this:

• instrui = to teach
• instruisto = teacher
• instruistino = female teacher

The suffix -in- marks female sex.

So the sentence specifically says that the teacher is female. If you used instruisto, that would simply mean teacher, without explicitly marking female in this form.

Because ni is the recipient, not the direct object.

In Esperanto, with doni:

• the thing given is the direct object
• the person receiving it is often introduced by al

So here:

• novan temon = a new topic
• al ni = to us

That matches the English pattern:

• give a new topic to us

If you said nin, that would make us a direct object, which is not what this sentence means.

Because novan temon is the direct object, and the adjective must agree with the noun.

Base form:

• nova temo = a new topic

As a direct object:

• novan temon

Both words get -n:

• temon because it is the direct object
• novan because adjectives agree with the nouns they describe in both number and case

This agreement is a very important feature of Esperanto.

Because nia instruistino is the subject of donos.

In the main clause:

• nia instruistino = our teacher
• donos = will give
• al ni = to us
• novan temon = a new topic

Since nia instruistino is the one doing the giving, it stays in the subject form, with no -n.

If she were the direct object, then you would see -n:

• Mi vidas nian instruistinon. = I see our teacher.

Esperanto has la for the, but it does not have a separate word for a/an.

So:

• la rezultoj = the results
• novan temon = a new topic

The sentence uses la rezultoj because the results are understood as specific results already known in the situation. But novan temon is indefinite, so there is no article before it.

That is very normal in Esperanto:

• Mi havas libron. = I have a book.
• Mi havas la libron. = I have the book.

Poste means later or afterward.

In this sentence, it tells us when the teacher will give the new topic.

Esperanto word order is fairly flexible, so poste can often move without changing the basic meaning:

• ...nia instruistino donos al ni novan temon poste.
• ...nia instruistino poste donos al ni novan temon.
• ...poste nia instruistino donos al ni novan temon.

These versions are all understandable. The choice mainly affects emphasis and style.

Yes. Because Esperanto uses endings and prepositions clearly, word order is more flexible than in English.

For example, these are all possible:

• nia instruistino donos al ni novan temon poste
• nia instruistino donos novan temon al ni poste
• poste nia instruistino donos al ni novan temon

The clearest and most neutral version is usually the one in the original sentence, but other orders are possible.

The comma separates the se clause from the main clause:

• Se la rezultoj estos bonaj,
• nia instruistino donos al ni novan temon poste.

This is similar to English punctuation with an introductory if clause. It helps the reader see the structure more easily.

In Esperanto, punctuation is somewhat flexible, but this comma is very natural and standard.

It has two parts:

1. A condition:

   • Se la rezultoj estos bonaj
   • If the results will be good / If the results turn out well

2. The result:

   • nia instruistino donos al ni novan temon poste
   • our teacher will give us a new topic later

So the overall pattern is:

• Se ... , ...
• If ... , then ...

This is a very common and useful sentence pattern in Esperanto.