UPDATED January 2016: Watch Actual YouTube “how to add Google+ Manager” for 2016 by clicking here
Here is a quick and easy step by step instruction to help you give someone “manager” access to your Google + Branding or Google+ Local page. In order to add managers, you must be the “Owner” of your Google+ page. Keep in mind, “owner” is linked to a particular email address, so make sure you are in that Gmail email when trying the steps below.
How to add a manager or communications manager to your Google+ page
Step 1: (Must be in the Google+ page)
Once you have added the email address of the person you want to make Manager of your Google+ page and clicked “invite”, they will receive notification of the invite from Google. Once the email is received, it will have instructions to the new manager of how to access the page and work within your Google+ page. They will also have to abide by all user terms.
Managers have a lot of access and abilities within each page, so choose wisely who you wish to have access. The two major abilities they do not have is to delete the page or assign their own managers. Only the owner of the page can do that.
For a full list of administrative rights for Managers of your Google+ page, you can read it directly from Google here: Manager Rights
How to make someone Communications Manager of your Google+ page:
For even stricter access to a page, you may want to select “Communications Manager” for someone’s access. Communications Manager only allows a person to post, view insights and respond to reviews. This can be done be done by selecting the “Communications Manager” option in the left hand bottom side of the invite box. See below