Note: Only Super Admins/Admins can do this.
To make sure your managers can access the information of people they manage and approve their holidays, you need to make them Line Managers on Charlie.
You can easily make someone a Line Manager from one of two places:
Head to 'People' tab on the lefthand side.
Using the check boxes next to team member's names, select all the people you want to report to a certain Line Manager.
Select 'Change Line Manager' button on top of the page.
Select the name of the Line Manager and select 'Update Line Manager' to save.
Team Member's Profile page:
Head to the team member's Profile page.
Click on their 'Employment' tab.
Find the Line Management section (on the right hand side).
Select 'change manager'
Select the new line manager from the drop down menu and click 'update line manager'
Note: Line Managers only have access to their direct reports, they won't have access to indirect reports such team members their direct reports manage.
Once you start adding Line Managers, Charlie will automatically build an org chart based on this structure. This is visible from the People tab.