La proceduro de resendo estas simpla.

In Esperanto, -o marks a noun. So proceduro means procedure as a thing or concept.

You can compare:

• proceduro = procedure
• simpla = simple (adjective)
• resendo = return / sending back (noun)

La is the definite article, meaning the. Unlike English, Esperanto uses just one form:

• la proceduro = the procedure

It does not change for gender, number, or case.

De usually means of. Here it links the two nouns:

• la proceduro de resendo = the procedure of returning / the return procedure

This is a very common Esperanto pattern:

• la nomo de la urbo = the name of the city
• la tempo de foriro = the time of departure

So de resendo tells you what kind of procedure it is.

Resendo comes from:

• re- = again, back
• send- = send
• -o = noun

So literally it is something like a sending back. In context, it often means return, sending back, or reshipment, depending on the situation.

Because it ends in -o, it is a noun. Esperanto often turns actions into nouns very easily:

• sendi = to send
• resendi = to send back
• resendo = a sending back / return

This is similar to English expressions like the return process or the act of returning.

Simpla is an adjective, and adjectives in Esperanto end in -a.

So:

• simpla = simple

Since it describes proceduro, it uses the adjective ending -a.

The -n ending is usually used for the direct object or for certain motion expressions. In this sentence, simpla is not a direct object. It is part of the predicate after estas.

So:

• La proceduro ... estas simpla. = The procedure ... is simple.

Both proceduro and simpla are just naming and describing the subject, not receiving an action.

Estas is the present tense of esti, meaning to be.

So:

• estas = is / are / am

In this sentence:

• La proceduro de resendo estas simpla.
• The return procedure is simple.

Esperanto uses estas just like English uses is here.

The normal, most natural order is:

• La proceduro de resendo estas simpla.

That is:

• subject: La proceduro de resendo
• verb: estas
• complement: simpla

Esperanto word order is fairly flexible, but this standard order is the clearest and most common, especially for learners.

Yes. Depending on context, English might say:

• the return procedure
• the procedure for returns
• the procedure for sending something back
• the return process

Esperanto often uses de where English may prefer a compound noun or a different preposition.

Because everything is singular here.

In Esperanto:

• nouns take -j for plural
• adjectives also take -j if they describe a plural noun

So if it were plural, you might see:

• La proceduroj de resendo estas simplaj.
• The return procedures are simple.

In your sentence, proceduro is singular, so simpla is singular too.

Yes. In Esperanto, adjectives agree with the nouns they describe in number and case.

Here both are:

• singular
• no -n

So:

• proceduro
• simpla

If the noun changed, the adjective would change too:

• proceduroj simplaj = simple procedures
• proceduron simplan = a simple procedure (as direct object)

Not exactly by itself. Resendo specifically suggests sending back / returning something. It does not automatically mean refund, which is a different idea.

So the sentence is best understood as:

• The return procedure is simple
• The procedure for sending it back is simple

If you specifically wanted refund procedure, Esperanto would usually use different wording.