How to customize cell of FSCalendar?

I'm using FSCalendar in my project and I want below calendar.

enter image description here

but here is default form of FSCalendar.(only editing border radius and some petty things.)

enter image description here

Becoming my blueprint calendar, I maybe have to edit size of date cell, gap of cells(maybe should be 0), position of date number and some else.

How to customize cell of FSCalendar?

I'm trying to search github and other questions, but have a problem to understand.