It's easy to confuse used to do and be used to. Both forms look alike, but they have very different meanings and structures.
First let's look at used to do, or used to + verb. When I say I used to do something, I mean that I did something regularly in the past which I no longer do now. For example, "When I was a child, I used to fight with my siblings, but now we get along." We can also use used to do to talk about something that was true in the past but is not true now, for example, "Drinking alcohol used to be illegal in the U.S." In other words, drinking alcohol was illegal in the past, but it is no longer illegal.
Be used to means something different. If you are used to something, you are accustomed to it. It is normal or usual for you. Be used to is always followed by a noun or gerund (verb ending in ing). For example, I can say I am used to the rain, or I can say that I am used to staying up late.
Used to Do vs Be Used to Grammar Quiz
Used to Do vs Be Used to Lessons: