Help with WifiKit PinOut - Basic Question

Hi - I am new to ESP32 programming - have Micropython up and running.

Looking at the schematic, it looks like all the Pins have multiple different roles. I just need some pins to connect to a HCSR04 ultrasonic sensor, a couple of LEDs and a button.

Can I use any pins, or are there a bunch that have specific roles that using them would create a problem?

I understand that the OLED display uses SPI, so I shouldn’t use 18-23, but can I use Pin 0 to access the on-board button, or should I worry about the yellow CLK1 (control) use?

I’m guessing 36-39 are to with battery voltage, so they are out. But what about 32-33 marked XTAL? And it looks like 25 is out because of the LED.

Feel free to point me to a resource I can read to learn about all of this… I did try googling but did not get very far.