In the right upper corner, select the Setting tool which will appear on the page of 'Dashboard'.
Click on 'Permission group' at the centre of the page.
You will see an overview of all permission groups. Select the one you would like to adjust.
Once you open the permission group, click on the 'Actions' button at the top right corner.
A small drop down will appear. Select 'Edit'.
Four categories will appear on the screen. At the top of the page you will find the list with All available permissions and Selected permissions for this permission group. Select the permission you would like to add from the list on the left and click on 'Update permission group' at the bottom of the page to save your choice.