When you create a campaign, it will be labeled as "waiting" until you send traffic to the campaign pages. When the campaign pages receive traffic, the status will change to "learning".
The "Collecting" status indicates that each of your variations has at least 300 impressions. When the test determines the winner based on statistical significance, the title will be changed to "Winner." You can also manually end the campaign test if you determine you have gathered enough data. In these cases, the status will be "Completed."
If no traffic is directed to the campaign page in two months, the status will be changed to "done."