When you first switch on your smartphone it will automatically enter a process that is known as set up.
During set up you will be invited to create a Google Account, or connect to your existing account, so that information can be saved and synchronised online. Your account-id / email address will take the form of joe.bloggs@gmail.com which you use with your chosen account password to gain access to all Google Services.
Make sure to make a note of both your account-id and password as they are required for account access and should not be disclosed to anyone. Also make a note of recovery email address and phone number used during account registration,
Just about all smartphones feature two physical switches - the on/off button and the volume control. Some older phones also had up to three navigation buttons [usually at the bottom of the screen] but in general these have been replaced by 'soft' buttons which appear along the bottom or the side of the screen depending upon whether you are in both portrait or horizontal mode.
You should consult your manual [or google-it online] to become familiar with the functions of the different buttons.
Once your smartphone is up and running you should take time to explore it's menu system so that you are familiar with finding where you can adjust features like brightness; volume; other hardware and software settings; which icons appear on your home screen; widgets; launchers etc.
Everything mentioned on this page is gone into in more detail on other pages of this site that you can easily find by using the site's navigation menus or the Search box.
Click here to read a quick guide from HowToGeek called "I Set Up These 5 Emergency Features on Every Android Smartphone"
Some smartphones comes with default settings for features that can be a real pain.
Click here to learn four useful tips to suppress them - especially the 4th entry for Caffiene that can be really handy for stopping your phone's screen going blank just when you didn't want it to.
Click here for Google Support page that explains what you should do.
Click here to see a HowToGeek article that exlpains what data gets backed up automatically by Android.
If the battery in your smartphone or tablet seems to need charging more and more frequently it could be time for action.
Click here to read an article by NextPit called "How to calibrate the battery on your Android phone or tablet"
Smartphones often come pre-loaded with Apps you probably don't need which can be a major cause of battery drain. Click here for a NextPit article called "Top 5 performance-killing apps you need to delete today" to learn how to remove these Apps and get battery performance.
Click here for an AndroidPit document that explains all about Gesture Control that was introduced with Android 10.
When a device is first set up the 'owning' username is created using the email address supplied [usually your Gmail a/c] but things may change over time.
Click here for a HowToGeek article called "How to Change Your Default Google Account on Android" should ever need to alter the 'ownership' of your device.