The link you followed is for a different setup (virtual users with postfix without
ispconfig), so its not for ispconfig 3.
my mail_acess table is empty how do i add data to it with ispconfig
This table is for relay users only, so it should be empty on most systems. It may not contain any maolbox users or domains. Only if you use your mailsystem as relay server e.g. in front of a outlook system without local mailboxes on the ispconfig server then you might have records there.
Have you run the ispconfig after you removed dovecot and choose to reconfigure services? Dovecot has to be completely removed so that no dovceot binaries are on the disk anymore, just disabling it is not enough. Aftewards you have to run a ispconfig update and choose to reconfigure services or the setup will fail.