Serum vs Beauty Balm

[Overthinker2016]

I have both of these from the Botanics range. What is the difference?
Do I wear both under moisturiser?

I think balms were more for cleansing..

I'm a massive fan of serums!

*thought

Beauty balms are like tinted moisturiser, but with more supposed benefits and slightly thicker coverage. So, after moisturiser instead of foundation. That's what I think