Adlerian psychology is built on a simple but very powerful idea: do not let the past define you, because your life is not determined by what happened to you, but by the meaning you give to what happened to you.
Freud believed more in a cause and effect model, where your childhood, trauma, and past experiences explain who you are today, but Adler strongly disagreed with this view, even though the two of them used to meet and discuss psychology together in Vienna in the early 1900s before their ideas split.
Adler argued that events themselves do not determine your life, but the interpretation and purpose you attach to those events, which means two people can go through the exact same experience and one can use it as a reason to suffer while the other can use it as a reason to grow.
In this view, the past is not a prison, it is material, and YOU are the one who decides what to build from it.