Because polyatomic ions are made of covalently bonded atoms, do they behave like simple covalent bonded atoms?
No, they behave like simple ions.
Even though they are made of covalently bonded atoms, they have a charge. So they behave as ions.
That makes it easy to balance equations that have polyatomic ions.
If we have to balance an equation like
(NH₄)₂SO₄ + Ba(NO₃)₂ → NH₄NO₃ + BaSO₄
we can mentally let NH₄ = M, SO₄ = X, and NO₃ = Y. Then the equation becomes
We balance this as
M₂X + BaY₂ → 2MY + BaX
When we put the symbols back in, we get
(NH₄)₂SO₄ + Ba(NO₃)₂ → 2NH₄NO₃ + BaSO₄
You will soon get used to it, and then you can do polyatomic ions in your head.