Three very useful constructions in the English language contain USED TO. They all are used with completely different meanings and this is what can make students feel a little worried or reluctant to use them. Hopefully my explanation will be clear and help you when using and understanding the usage.

USED TO - it basically is a phrase that means 'I did in the past, but I don't now'

We can use it to talk about our jobs, place of living, possessions, and hobbies or actions we no longer do or have now in the present time.

Example: I used to be an office manager - I am not, now, I'm a teacher
I used to live in Moscow - I don't live there now, I live in Lviv
I used to play football - It was my hobby when I was younger, but not now
I used to have an iPhone - It was a possession I had years ago, but now I don't have one

Note: We can only use used to if we did something more than once. So if you PLAYED tennis once in your life. You didn't use to play tennis, but you 'played once' or ' tried tennis once'

TO BE USED TO - basically means I am comfortable with something or doing something after something is new.

Imagine you start a new job. It's not going to be very easy at the start. After a couple of months. You will be USED TO it - comfortable with everything

Example: At first waking up early to start my job was hard, but now I am used to it. - It's no problem now
There were lots of different changes when I moved schools, but now I am used to them - at first it was hard and now you feel comfortable.

GET USED TO - This is the process of feeling comfortable. So before you ARE USED TO you have to GET USED TO something. Let's imagine you moved to a new country. At first everything would be new and you would need some time to process everything. This process is getting used to something. After this process finishes you then are used to it.

Example: The hardest part about moving country is the food. I am getting used to the different times they eat their meals here. - The process is still happening and I feel not so comfortable
I got used to driving on the other side of the road, but I am still getting used to the different signs I see when I drive - the process of driving on the other side of the road is over and I am used to it. I still don't feel comfortable with the signs, so this process is still ongoing. 

Questions
Are you getting used to anything now?
What did you used to do as a child?
What problems would people have to get used to if they moved to your city or country?
Was there anything you didn't get used to?