Installation

sudo apt install pinentry-qt scdaemon yubikey-personalization-gui

Importing public key

gpg --import < publickey.txt

With the yubikey attached check it finds it pass uses gpg2 so ensure gpg2 works as well.

Note that this steps seems to link the secrets on the card to device, so is required.

gpg --card-status
gpg2 --card-status

Should see sec# and ssb>

gpg --list-secret-keys $KEY-ID

Mark as trusted

gpg --edit-key $KEY-ID
gpg> trust
Your decision? 5 - I trust ultimately