If you are using a USB extension cable, cut it in half and expose the four cables. Keep the socket end, as the goal is to plug a controller into this cable.
Hook up the V+ / VBUS (Red) to the VBUS pin on your Pi Pico
Hook up the V- / GND (Black) to ground on your Pi Pico
Hook up D+ (Green) to one side of a 27ohm resistor and the other side to a unused digital pin.
Hook up D- (White) to one side of a 27ohm resistor and the other side to the digital pin directly after D+. For example, you can hook up D+ to GP2 and D- to GP3.
Connect a 47pF capacitor between D+ and ground
Connect a 47pF capacitor between D- and ground
Wiring Steps (without capacitor and resistor)
If you are using a USB extension cable, cut it in half and expose the four cables. Keep the socket end, as the goal is to plug a controller into this cable.
Hook up the V+ / VBUS (Red) to the VBUS pin on your Pi Pico
Hook up the V- / GND (Black) to ground on your Pi Pico
Hook up D+ (Green) to a unused digital pin.
Hook up D- (White) to the digital pin directly after D+. For example, you can hook up D+ to GP2 and D- to GP3.
Wiring for USB Host + PS2 or Wii emulation
Follow one of the above guides for GND, D+ and D-
Connect GND on the Pico to GND on the boost converter
Connect VSYS on the Pico to the input terminal on your boost converter
Connect the V+ / VBUS (Red) from your breakout or extension to the output pin on your boost converter
Configuring
Click on Add setting
Find and add USB Host inputs
Bind D+
Hit Save
If you plug in a supported controller, the tool should detect it and tell you what it is. Most controllers are supported, but things like the play and charge kit won't work over USB.