When you open up ClockOn from your computer you will asked to Login. 

See Logging into the ClockOn Application for the First Time

The Login button allows authorised users with valid user names and passwords to gain access to some or all of the ClockOn main screen options and to clock on and off.

NOTE: 

• The User Name or password may include up to 20 alpha numeric characters.
• The employee can clock on after logging in.