the Raspberry Pi 4 has six SPI controllers, six I2C controllers, and six UARTs – all on its 40-pin header. You can’t make use of all of these at once, but with up to four different connections ...
Everything needed for the Raspberry Pi comes in the CanaKit listed above, except for the SSD. Then, connect the red lead from the fan to pin #2, which is the five-volt direct current power supply pin.