Before you can begin, you need something to install. Download the DEB file you want to install and locate it with the file explorer on Ubuntu.
Right-click the DEB package and choose the option to open with Software Install.
When you're ready to begin the install, click Start Installation on the window that opens.
You will be prompted for your administrator password, confirm it in the window, if prompted.
Wait for the installation to complete. The time required for this step will vary depending on what you're trying to install.
If you want to remove the DEB package, you can uninstall it from the same Software Install window. Click Remove and then Remove again on the pop-up to uninstall the application.