Setelah makan, saya lap meja dengan serbet.

Both are possible.

In Indonesian, the subject is often omitted when it is obvious from context. In this sentence, saya in the main clause tells you who did the eating, so Setelah makan naturally means After I eat / after eating.

• Setelah makan = After eating
• Setelah saya makan = After I eat / after I have eaten

The version without saya sounds very natural and efficient.

Lap here is the informal, conversational verb form. The more standard or formal form is mengelap.

So these are both possible:

• Saya lap meja dengan serbet. → informal/everyday
• Saya mengelap meja dengan serbet. → more standard/formal

This kind of prefix-dropping is common in spoken Indonesian, especially in casual speech. A learner will often see the full form in textbooks, but hear the shorter form in real life.

Here, lap is functioning as a verb: to wipe.

That can confuse learners because related words also refer to wiping cloths, for example:

• lap / mengelap = to wipe
• kain lap = wiping cloth / rag
• lap meja can mean wipe the table if lap is a verb, or in another context could look like part of a noun phrase

In saya lap meja, it is clearly a verb because it comes after the subject saya and before the object meja.

Dengan means with, and here it introduces the tool or instrument used to do the action.

So:

• lap meja = wipe the table
• dengan serbet = with a napkin / with a cloth

It tells you what you use to wipe the table.

It depends on context.

Serbet often means napkin, especially a table napkin. But in some contexts it can refer to a cloth used for wiping. In this sentence, because it is used to wipe a table, English might translate it as napkin or cloth depending on the situation.

If you want to be more specifically wiping cloth, Indonesian often uses:

• kain lap
• lap

So serbet is possible, but the exact English word may vary by context.

Indonesian does not use articles like a, an, and the the way English does.

So meja can mean:

• a table
• the table
• just table in a general sense

You figure out which one is meant from context. In this sentence, English usually uses the table, but Indonesian does not need a separate word for the.

Indonesian verbs do not change form for tense the way English verbs do.

So saya lap meja could mean different things depending on context:

• I wipe the table
• I am wiping the table
• I wiped the table
• I usually wipe the table

Likewise, Setelah makan can mean after eating, after I eat, or after I ate. The surrounding context tells you whether it is a routine, a present situation, or a past event.

Yes. The basic word order is usually:

Subject + Verb + Object

So here:

• saya = subject
• lap = verb
• meja = object

Then dengan serbet adds extra information about the instrument.

So the structure is:

Setelah makan, + saya + lap + meja + dengan serbet

This is very normal Indonesian word order.

Yes. That would still be a complete sentence.

• Setelah makan, saya mengelap meja. = After eating, I wipe the table.

Adding dengan serbet simply gives more detail about how you do it.

Saya is the more neutral and polite word for I. It works in most situations, including writing and conversations with people you do not know well.

Aku is more casual and is used with friends, family, or in a more intimate tone.

So:

• saya = neutral/polite
• aku = casual/intimate

That is why textbook-style examples often use saya.