Adding new apps is your own responsibility.
You need to have an Apple ID to install new apps. If you don't have one, you can create it at appleid.apple.com.
When you have an Apple ID, click on the App Store icon on the iPad to locate new apps and download them.
When you return the iPad, we must erase all apps that were added. However, apps that you purchase with your Apple ID will be still be available to you through your Apple account, and you can reinstall them on another device.