bepaal means determine, decide, or sometimes indicate, depending on context.
In this sentence, it means that the label determines or tells us what should be recycled.
Because Afrikaans verbs usually do not change form in the present tense the way English verbs do.
So you get:
That same basic verb form stays the same.
wat means what here.
It introduces the clause what we recycle:
So the structure is very close to English: The label determines what we recycle.
herwin means recycle, recover, or reclaim, depending on context.
Literally, it has the idea of win back or recover again:
In environmental language, herwin is commonly used for recovering materials for reuse, so recycle is the natural translation here.
Yes, it is normal.
This part literally works like:
So wat ons herwin = what we recycle.
For an English speaker, this part feels familiar because the order is quite close to English.