First, you will need to add it to your server with this link : click here
A birthdays channel is a channel where messages will be sent on birthdadys.
You will need to do the following command :
!config birthdaychannel [your channel]
For example, you can do that :
Now, every member of your discord will need to set its birthday.
Now, Birthdays will wish birthdays to members of your discord !
Do you want to edit the message on birhtday ? See