Spotykamy się w barze.

Spotykać się is the standard verb phrase for to meet each other, to get together, or to meet up.

The się is not a separate word you translate directly every time. It is part of how this verb is normally used. In this sentence, it helps give the idea of a mutual meeting.

Compare:

spotykamy kogoś = we meet someone / we come across someone
spotykamy się = we meet each other / we are meeting up

So in this sentence, się is essential.

This is about aspect, which is very important in Polish.

spotykać się is imperfective
spotkać się is perfective

So:

spotykamy się = we meet / we are meeting / we get together
spotkamy się = we will meet

In other words, spotykamy się w barze is in the present-tense form of the imperfective verb, while spotkamy się w barze would normally mean we will meet at the bar.

Yes. Polish present tense often covers several English meanings, depending on context.

So spotykamy się w barze can mean things like:

we meet at the bar
we are meeting at the bar
we meet up at the bar

Context tells you whether it is habitual, happening now, or a planned arrangement.

Because the verb ending already tells you the subject.

spotykamy ends in -my, which shows we.

So Polish often leaves out subject pronouns when they are not needed.

You could say My spotykamy się w barze, but that would usually add emphasis, something like we meet at the bar.

barze is in the locative case.

After the preposition w when it means in or at a place, Polish normally uses the locative:

w domu = in the house
w szkole = at school / in school
w barze = in the bar / at the bar

That is why bar changes to barze.

The dictionary form is bar. In the locative singular, it becomes barze.

So:

bar = bar
w barze = in the bar / at the bar

This is a normal pattern for many masculine nouns after w, o, and na when the locative is needed.

It can correspond to either in or at in English.

Polish w mainly indicates being inside a place or within that location, but in English we often say at the bar even when Polish uses w barze.

So w barze can naturally be translated as either:

in the bar
at the bar

The best English choice depends on context and style.

Polish word order is fairly flexible, although some orders sound more natural than others.

The neutral order here is:

Spotykamy się w barze.

You can also say:

W barze spotykamy się.

That puts more emphasis on where you are meeting.

The position of się is somewhat flexible, but it usually stays close to the verb. Spotykamy się w barze is the most natural standard version.

Yes, sometimes.

Spotykać się z kimś can mean to be seeing someone or to date someone, depending on context.

For example:

Spotykam się z Anią.
This could mean either I am meeting Ania or I am dating Ania, depending on the situation.

But in Spotykamy się w barze, the most natural meaning is simply we are meeting up at the bar, not a romantic one.

się is pronounced roughly like shye or sheh to an English speaker, although the exact Polish sound is a bit different.

In everyday speech, the nasal sound in ę is often weakened, so learners will often hear something close to sie.

A rough pronunciation of the whole sentence is:

spo-ty-KA-my shye v BAR-zhe

That is only an approximation, but it is a useful starting point.