Picroft is specifically packaged to run on a Raspberry Pi 3 or 4. It is built on top of the official Raspbian Buster Lite and is available as a disk image ready to be burned to a microSD card. For complete instructions see Getting started with Picroft.

For Mycroft to hear you and respond to you, just connect a speaker and a USB microphone to your Pi. See here for a rundown of which components have been found to work best.