Once you have created the users at https://cp.hostallapps.com; then you need to login into your SharePoint site as a Administrator and provide permissions to the newly created user by following these steps.
NOTE: If you have not created the user yet; then, please follow the steps located here.
If you have created the user at https://cp.hostallapps.com then you need to follow the steps given below after logging into the SharePoint site as administrator.
1. Click on Site Actions.
2. Click on Site Permissions.
3. Click on Grant Permissions.
4. In the Users/Groups section enter the First Name and Last Name of the user.
5. Just below the “Users/Groups:” box there is “Check Name” icon with blue check mark. Click that and the name should get underlined.
6. Give the permissions.
7. Scroll to the bottom and hit OK.