How do I log into BizForm after receiving the invitation?

Vital BizForm admin can invite users to the system, but how can the invitee log into the system after receiving the invitation?
First, the invitee will receive an email invitation. After clicking the link included in the email, the login menu will show up.
If the invitee has already registered a GSSCLOUD account, he/she can log in directly; if not, please sign up first!