Your client is interested in running a campaign for 1 month and then do a...

You can ONLY set up a brand lift study through a Facebook Account Representative. 

Once a study is created, the campaign's target audience is separated into a test group and a control group. The test group contains people eligible to see your ads, and the control group contains people who won't see your ads. 

The people within the test group that actually see your ads become part of the exposed group.

The exposed group and control group are then polled, and the difference in responses between the 2 groups is analyzed.