The OLED display is a bit thinner as the regular LCD and needs an updated cover, holders, and knob. STLs can be found here: https://github.com/Caribou3d/CaribouCartesian/tree/master/STL/01_full-kits/Frame/Einsy/OLED.
You need a firmware that supports the OLED (Prusa firmware does not).
Firmware for Caribou and Prusa can be found here: https://caribou3d.com/en/content/10-caribou-mk2-mk25s-mk3s-software
Source code can be found on github: https://github.com/Caribou3d/CaribouMK3s-Firmware.
Included: two flat ribbon cables (70cm)