That's just how this sort of skirt is made

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A: I'm just making your skirt smooth and flat.
B: I don't want my skirt to be smooth and flat.
A: But why, that's what's ironing for. To make things smooth and flat.
B: Not with this kind of skirt. Look at the pleats.
The folds in the material.
A: Oh, oh, I see the pleats, but why is this material folded like that into
lots of little pleats?
B: That's just how this sort of skirt is made.
A: How do you iron it?
B: You must iron each pleat individually.

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B: That's just how this sort of skirt is made. ?

What does "just" mean in this sentence?

Does it mean "only" or does it mean "exactly"?

Thank you