If you go into a division and you can see the add section button, but you are unable to click on it, it means that you do not have the required permission. You can ask your manager or system owner to give you the permission.
As a system owner or manager, you can also give the permission by following steps below:
Use the organisation structure to search and find the division you want to add a section for and click on it.
Click Edit button on the bottom left
Buttons will be highlighted in yellow after.
Click on the Add Section.
In the pop-up window click on Can Add.
Select the role that you want to be able to add new section.
Eye icon has to turn green.
Click Save.