Campaign's Daily Send Count
Each campaign has a daily send count, which determines the number of mailings sent each day once you activate your campaign.
Each evening, Pebble will gather your active campaigns and send a batch of mailings according to the campaign's daily send count. Mailings will be sent according to the row number of your list file.
Mailers go out every day and will be processed overnight.
If you'd like to send an entire campaign in one day, set the campaign's daily send count to a really large number that is greater than the total number of properties of your mailing campaign.
To do this, click on Edit in your Campaign
Then change the number in the daily send count (in the example we've selected 1,000,000) and then click Save Campaign
Your campaign will then show the changes.