Add me to /etc/pacman.conf, example:

/etc/pacman.conf:
		[somerepo]
		Server = [this server]:[port]/$repo

Download my key (/public.key), then add it with # pacman-key --add public.key

Since nobody trusts me, you need to sign the keyid. Get the keyid with gpg --show-keys public.key

Then locally sign it with pacman using # pacman-key --lsign-key [the id]