When you schedule your ads, you can control when you run them and how they are delivered.
You can find out more about scheduling here.
You can easily turn ads on and off in certain days of the week on The Next Ad. You can find Day parting if you go to Campaign settings, then click on Advanced and choose the Day Parting tab. Once there, you will find two different options: Run ads all the time or Run ads on a schedule. To enable Day Parting select the latter.
Once you've clicked on that box, you'll be able to select at what time and on which days you want your ads to be shown. Day Parting only works with lifetime budget, so bear in mind that you won't be able to set it up if you have a daily budget.
It's good to know that ad scheduling always operates in time zone of the target audience, not for the time zone of the ad account. If you want to run an ad in Los Angeles on Saturdays between 6-9 p.m., those ads will be delivered in L.A when it's 6-9 p.m. in that timezone.
You can find out more about Day Parting here.
If you want to edit Day Parting, your campaign needs to be still in draft. Unfortunately, when a campaign has the status of published/running it's not possible to edit day parting anymore. When you want to edit it in a published campaign it's possible to copy the campaign. Now you can pause the first campaign, and then edit day parting in the "new" copied campaign.