As an administrator you can apply permissions in bulk to users by using the bulk change feature.
Quick Steps
Click on settings in the left navigation menu
Select users
Select all the users you want to add, or remove, a permission to. Do this by selecting the empty block next to the user.
Click on the Bulk Change button
Select the Properties tab at the top
Click on Permissions and choose the correct action from the options:
Add
Replace All
Find And Remove
Remove All
Choose the relevant permissions in the second text box for the selected action
Select the green Apply button
If multiple users were selected, the permissions will be added or removed for all
The video demonstrates how to use bulk change to remove a permission and add a permission in bulk:
Read more about bulk change and the available actions and properties that can be amended in bulk.