It's a difficult to wrap your human brain around the Trinity because it's a God thing and outside our understanding and experience. I don't understand how a plane works, but I trust that it does every time I board one. There are a few analogies that can help explain the Trinity but none of them are perfect.
EGG: The Trinity is like an egg, it has a shell, yolk and egg white. All three are different but at the same time they are all part of the egg.
FAMILY: I am a wife, mother and daughter. The three roles are very different, but I fulfil all of them.
You won't find the word, Trinity, in the Bible. All three persons of God are referred to throughout the Bible but not usually together. Matthew 28:19 is what Jesus told his followers before he returned to heaven, So go and make followers of all people in the world. Baptize them in the name of the Father and the Son and the Holy Spirit.
I love this definition from Bill Pratt on https://www.toughquestionsanswered.org. The Father is the Source, the Son is the Means, and the Holy Spirit is the Effector of salvation—it is He who convicts, convinces, and converts.
Short and sweet inspirations for Christian teen girls.