1) i expect there is a typo on github
manufacturer's data sheet is boss.
2) the two highlighted resistors are pull ups.
EN and IO0 (?) connect somewhere on the ESP-WROOM-32 (U3)
when the switch is open, the resistors connect those pins to VCC
and so are pulled high, logic 1 (hence pull up)
when the switch is pressed, those pins are connected to ground (logic 0)
3) it is standard practice to put a small bypass capacitor on every power pin of every
digital IC.
sometimes it is 0.1 uF, sometimes 1.0 uF, sometimes they alternate.
the purpose is to help hold up the VCC when the chip draws current
and to bypass high freqency signals to ground
sometimes, small series resistor is included, with the capacitor
between the resistor and the power pin
look up bypass capacitor
4) I don't know what "... the capacitor is before or after the ESP-WROOM-32's VCCs pin?" means.
Bypass capacitors should be placed as close to the VCC pin as possible.
what do you mean by before or after?