In order to set a schedule for a campaign, first, you should set the end date in the "Information" step of campaign creation;
Once the end time is set, you should choose "Lifetime Budget" in the "Budget" step;
Lastly, in the "Budget" step, you can set the schedule for the campaign for the hours you want the campaign to run;
The campaign will start running on the day you want it to start and end in the day you want it to stop. The campaign will use the "Lifetime Budget" you set throughout the campaign. You can choose to run ads all the time in the timeframe of the campaign or you can choose a schedule for them.