To setup your Sellr Account, you will need to accept the email invitation you were sent. 

Find the email from called "Invitation instructions". In that email you will find a link to "Accept invitation". Once you click on that link, you will be able to setup a password. 

The password will require 8 characters. Input a password and click the button to continue. 

Once you setup your password, you'll be directed to your store and products.