Jacky's answer is spot-on, but I thought I would elaborate a bit.
Option 1: Via New Deployment Dialog
When you go to create a deployment from a Deployment Plan, you'l see that you have 2 choices:
Select that first one, as Jacky said, to run pre-deployment, but then wait. You'll now have the option to schedule available to you on the right pane:
Option 2: Via Deployment Pipeline Overview
View the pipeline:
You need to select the app, project and environments you are working with.
Assuming you manually deployed to one environment, you can then control how to promote to the next environment in the pipeline:
Using the Customize Promotion option let's you specify a schedule:
Option 3: Use CDE
If you have CDE, you can also use it to schedule the deployment. One benefit of this approach is that the pre-deployment step does not occur immediately. Rather, CDE triggers the deployment to begin via the REST API, so the pre-deployment and deployment steps happen at the scheduled time.