Managers at the company you are working for should provide you with your initial login information to set up your HotSchedules account. This is most often provided on a Welcome Sheet, a piece of paper that they print out with instructions on how to log in for the first time.
They could potentially also email you your login information, but you would need to confirm your email address with HotSchedules first. First, you would receive an email asking you to select a confirmation link. Once the email is confirmed, then you could receive an email invitation to log in.
However, if you have not received a Welcome Sheet or any initial login information from your manager, you will need to contact your manager. They are responsible for granting access to new users and getting accouts created. Additionally, if you lose the login information before you set up your account, you will need to get with your manager again to retrieve another Welcome Sheet.