What phone do you have? If it's a smartphone, open the cloud app from your app drawer (the phone should have it pre-installed for you) and follow the prompts to backup your Contacts, Calls, Messages, Music, Photos, etc.
You can set it to automatically backup at set times, and to backup over wifi to conserve your data.
Apps need to be reinstalled on new devices, and your app list is stored with your respective OS app store - Googly Play, Apple, Windows stores.
