renderDay for custom day icon

[annaolchowik]

<DayPicker
month={month}
renderDay={renderDay}
fromMonth={fromMonth}
pagedNavigation
disabledDays={[{ daysOfWeek: disabledDaysOfWeek }, { before: today }]}
onDayClick={handleDayClick}
modifiers={modifiers}
modifiersStyles={modifiersStyles}
/>;

I have below questions:

1. How to handle now disabling weekends on the calendar?
2. How to handle custom day rendering, for example day with icon?