Jeśli znowu zdarzy się taki bałagan, posprzątamy go od razu.

Yes. Jeśli means if and introduces a condition.

In this sentence:

Jeśli znowu zdarzy się taki bałagan, posprzątamy go od razu.

the first part means If such a mess happens again..., and the second part gives the result: ...we will clean it up right away.

A very similar word is gdyby, but that usually introduces more hypothetical or unreal situations, like if it were to happen or if it happened in a less likely sense. Here, jeśli is the normal choice.

Because zdarzyć się is a reflexive verb meaning to happen.

So the basic dictionary form is:

zdarzyć się = to happen, to occur

The się is part of the verb here. It is not optional.

Examples:

• To się zdarza. = That happens.
• To się zdarzyło. = That happened.
• To się zdarzy. = That will happen.

In your sentence, zdarzy się taki bałagan literally means something like such a mess will happen/occur.

Polish usually does not need a separate word like will. Future meaning is often built into the verb form itself.

Here, zdarzy się is the 3rd person singular future of the perfective verb zdarzyć się.

So:

• zdarza się = it happens / it is happening repeatedly
• zdarzy się = it will happen

Polish perfective verbs often form a simple future with one word, unlike English, which usually uses will.

Yes, znowu means again.

So:

• Jeśli znowu zdarzy się taki bałagan... = If such a mess happens again...

A close synonym is znów. Both are common:

• znowu
• znów

In many contexts they are interchangeable.

Bałagan means mess, disorder, or chaos depending on context.

Taki bałagan means such a mess or this kind of mess.

So taki adds emphasis or points to the type/degree of mess:

• bałagan = a mess
• taki bałagan = such a mess

This is very natural in Polish when referring to a situation that is noticeable, annoying, or familiar.

Because posprzątamy means we will clean up / we will get it cleaned up completely, while będziemy sprzątać means we will be cleaning or we will clean in a more ongoing sense.

This is an aspect difference:

• sprzątać = imperfective, focuses on the process
• posprzątać = perfective, focuses on completion

So:

• będziemy sprzątać = we will be cleaning
• posprzątamy = we will clean up, finish cleaning

In this sentence, the idea is clearly that the mess will be dealt with completely, so posprzątamy is the natural choice.

Go means it and refers back to bałagan.

Since bałagan is masculine singular, the pronoun is:

• go = him/it in certain grammatical contexts

Here it means it:

• posprzątamy go = we will clean it up

Even though English says clean up the mess, Polish can use a pronoun once the noun has already been mentioned.

Yes, you could say posprzątamy od razu, and it would still be understandable from context.

But go is used because it clearly refers back to bałagan and makes the sentence more explicit:

• posprzątamy go od razu = we’ll clean it up right away
• posprzątamy od razu = we’ll clean up right away

Both are possible. Including go sounds very natural because the speaker is directly referring to that specific mess.

Od razu means right away, immediately, or straight away.

Examples:

• Zrób to od razu. = Do it right away.
• Odpisał od razu. = He replied immediately.

In your sentence:

• posprzątamy go od razu = we’ll clean it up right away

Yes, Polish word order is more flexible than English word order, because grammatical endings carry a lot of information.

The version you have is very natural:

• Jeśli znowu zdarzy się taki bałagan, posprzątamy go od razu.

But some rearrangement is possible for emphasis, for example:

• Jeśli taki bałagan znowu się zdarzy, posprzątamy go od razu.

This still means the same thing, but the emphasis shifts slightly.

A few notes:

• się often moves around in the sentence, but not completely freely
• the most neutral word order is usually the best one for learners to copy
• Polish word order is often used to highlight what is new, important, or contrasted

It describes a real, possible future condition.

That is why Polish uses:

• Jeśli = if
• future/perfective forms like zdarzy się and posprzątamy

It means something like:

• If this kind of mess happens again, we’ll clean it up right away.

This is different from a more hypothetical or contrary-to-fact sentence, which would use forms like:

• Gdyby..., to...
• often with past-tense-like forms plus by

For example:

• Gdyby znowu zdarzył się taki bałagan, posprzątalibyśmy go od razu.
• If such a mess happened again, we would clean it up right away.

So your original sentence is more direct and realistic.