To invite and collaborate with up to two team members in the free version:
- Login and go to Profile > My profile
- At the left, enter the email address of the the person you're inviting. That email address should be the email address that person used to register with kantask.
- Click "Invite"
The team member you're inviting has to repeat that same process in her/his kantask application, i.e. inviting you.
You'll finally need to share any workspace, project and board where you want to collaborate together.