Superamos el problema juntos.

Superamos can be either:

• present simple: we overcome / we get past
• preterite (past simple): we overcame / we got past

This happens because for regular -ar verbs, the nosotros form is the same in the present and the preterite:

• superamos = present
• superamos = preterite

So you need context to know which one is meant. In real life, surrounding sentences or the situation usually makes it clear.

Spanish often leaves out subject pronouns because the verb ending already tells you who the subject is.

Here, superamos tells you the subject is nosotros/nosotras = we.

So:

• Superamos el problema juntos.
• Nosotros superamos el problema juntos.

Both are correct, but the version without the pronoun is more natural in many situations.

You might include nosotros only for emphasis, contrast, or clarity:

• Nosotros superamos el problema, no ellos.
  We overcame the problem, not them.

Spanish usually uses an article with nouns more often than English does.

So el problema means the problem, referring to a specific problem already known in the conversation or context.

Compare:

• Superamos el problema. = We overcame the problem.
• Superamos un problema. = We overcame a problem.

Leaving out the article here would normally sound incomplete or unnatural.

Juntos means together.

It comes from the adjective junto (together / close / joined), but in sentences like this it functions a bit like an adverb in English.

It agrees with the people involved:

• juntos = masculine plural, or mixed group
• juntas = feminine plural

So:

• Superamos el problema juntos.
  used for a group of men, or a mixed group
• Superamos el problema juntas.
  used if the speakers are all female

This is very common in Spanish: words that express how people do something can still show gender and number agreement.

Yes. If the group is entirely female, you can say:

• Nosotras superamos el problema juntas.

And even without the pronoun, the feminine form of juntas already gives a clue:

• Superamos el problema juntas.

That tells the listener the speakers are female.

If the group is mixed or all male, Spanish normally uses the masculine plural:

• Superamos el problema juntos.

Yes. Spanish word order is more flexible than English word order.

These are all possible:

• Superamos el problema juntos.
• Juntos superamos el problema.
• Superamos juntos el problema.

They all mean roughly the same thing, but the emphasis changes slightly:

• Superamos el problema juntos.
  neutral, very natural
• Juntos superamos el problema.
  puts more emphasis on together
• Superamos juntos el problema.
  also possible, with juntos placed closer to the verb

The original sentence is a very normal, natural choice.

This is a very useful distinction.

• superar un problema = to overcome a problem, get past it, get through it
• resolver un problema = to solve a problem

They are similar, but not identical.

Superar focuses on successfully dealing with the difficulty.
Resolver focuses on finding the solution.

So:

• Superamos el problema juntos.
  We overcame the problem together.
• Resolvimos el problema juntos.
  We solved the problem together.

Sometimes both could fit, but superar often sounds a bit broader or more emotional.

Because problema is one of the common Spanish nouns that end in -a but are still masculine.

So it is:

• el problema
• un problema
• este problema

This is because many words of Greek origin ending in -ma are masculine in Spanish, for example:

• el problema
• el sistema
• el tema
• el programa

So even though -a often suggests feminine gender, it is not a guaranteed rule.

In standard Spain Spanish, it is pronounced roughly like:

soo-peh-RAH-mos

A few details:

• su = like soo
• pe = short peh
• stress is on ra: su-pe-RA-mos
• the s is clearly pronounced
• the r in superamos is a single tapped r, not a strong rolled one

And:

• problema = pro-BLE-ma
• juntos = HUN-tos or YOON-tos is not correct; the Spanish j is a throaty sound, especially in Spain

So the whole sentence is approximately:

soo-peh-RAH-mos el pro-BLE-ma HOON-tos

That is only an approximation, but it may help.

Yes, it sounds completely natural.

It is short, clear, and idiomatic. A native speaker could easily say it in many situations, for example:

• after dealing with a difficult situation
• when talking about teamwork
• when remembering something hard you got through as a group

It works well in both literal and metaphorical contexts:

• a practical problem at work
• a family difficulty
• an emotional challenge
• a crisis or obstacle

So this is a very normal Spanish sentence.