Forsitan cras ad puteum iterum ibimus.

Because ibimus is the future tense of ire, meaning to go.

It breaks down like this:

• i- = the verb stem from ire
• -bi- = a marker often used in the future tense
• -mus = we

So ibimus means we will go.

This verb is a little irregular, so its forms are worth memorizing:

• eo = I go
• is = you go
• it = he/she/it goes
• imus = we go
• itis = you all go
• eunt = they go

Future:

• ibo = I will go
• ibis = you will go
• ibit = he/she/it will go
• ibimus = we will go

Latin often leaves out the subject pronoun because the verb ending already tells you who is doing the action.

In ibimus, the ending -mus means we. So Latin does not need to say nos unless it wants extra emphasis.

So:

• ibimus = we will go
• nos ibimus = we will go, with stronger emphasis

Because ad means to or toward, and after ad, Latin normally uses the accusative case.

The dictionary form is puteus = well.
But after ad, it becomes puteum, which is the accusative singular.

So:

• puteus = the well
• ad puteum = to the well

This is a very common Latin pattern:

• ad villam = to the house/farm
• ad urbem = to the city
• ad aquam = to the water

Because Latin nouns change form depending on their role in the sentence. This is called case.

Puteus is a second-declension masculine noun. Its accusative singular ending is -um.

So the forms are:

• nominative singular: puteus = the well
• accusative singular: puteum = the well, when used as a direct object or after certain prepositions such as ad

Since ad takes the accusative, you get ad puteum.

Cras means tomorrow. It is an adverb, not a noun.

That means it does not change its form for case, number, or gender. It simply gives information about when the action happens.

So in this sentence:

• cras = tomorrow
• ibimus = we will go

Together: tomorrow we will go

Forsitan means perhaps or maybe. It shows that the speaker is not fully certain.

So instead of a definite statement like:

• Cras ad puteum iterum ibimus = Tomorrow we will go to the well again

you get:

• Forsitan cras ad puteum iterum ibimus = Perhaps tomorrow we will go to the well again

It adds uncertainty to the whole statement.

Yes. In a sentence like this, forsitan works naturally with the future indicative ibimus.

Older or more formal Latin can sometimes use forsitan with the subjunctive, and learners may notice that in other texts. But using it with a future indicative like ibimus is entirely understandable and normal in a sentence of this kind.

So here, the idea is simply:

• perhaps
• tomorrow
• we will go

Iterum means again or a second time. It is an adverb.

In this sentence, it tells you that the action of going will happen again:

• iterum ibimus = we will go again

Because Latin word order is flexible, iterum can often move around without changing the basic meaning. But its most natural interpretation here is that it modifies ibimus.

Latin has a much freer word order than English because grammatical endings do a lot of the work that word order does in English.

English usually prefers:

• Perhaps tomorrow we will go to the well again.

Latin can say:

• Forsitan cras ad puteum iterum ibimus

and still be clear, because:

• ibimus already tells you the subject is we
• ad
  • accusative shows direction
• adverbs like forsitan, cras, and iterum can often move around

So Latin word order is often used for style, emphasis, or rhythm, not just grammar.

Yes, often they could.

For example, these would still mean roughly the same thing:

• Cras forsitan iterum ad puteum ibimus
• Ad puteum cras forsitan ibimus iterum
• Iterum cras ad puteum forsitan ibimus

The exact emphasis may shift a little, but the basic meaning stays the same because the endings and prepositions show the grammar clearly.

The version you were given is a perfectly natural way to say it.

Because ad usually indicates motion toward a place, not location in a place.

So:

• ad puteum = to the well
• apud puteum or another expression would be needed for the idea of being near or at the well
• a different construction would be used for being in a place

Since the verb is ibimus = we will go, a phrase of motion makes perfect sense:

• we will go to the well

A simple way to divide it is:

• Forsitan = perhaps
• cras = tomorrow
• ad puteum = to the well
• iterum = again
• ibimus = we will go

So the sentence is built from:

• an adverb of uncertainty
• an adverb of time
• a prepositional phrase showing direction
• an adverb of repetition
• the main verb

This is a good example of how Latin can place several adverbs before the verb and still remain clear.