Steps: For Footer widgets, go to homepage customize>widgets. You can find 4 widgets footer widget 1 to 4. For Demo select the widget first (Footer widget 1). After it, click on Add a Widget. Search the appropriate widget, maybe Text, Recent Posts, and Custom Menu etc. And finally, click on save & publish.
Another Step to add a widget.
Step 1: Go to the backend. Click on Appearance>Widgets.
Step 2: Select available widgets and assign to the respective widgets. After Selection click on save and view the homepage for the change.