When you read a story, it is often written in the third person (using he and she, rather than I and we). You probably know the story of Cinderella. Look at this passage from it.
After she had helped her stepsisters get ready for the ball, Cinderella sat down by the fire, exhausted. She watched them leave and then burst into tears of despair.
Suddenly there was a burst of light and a fairy appeared in front of her.
'Don't be alarmed', said the fairy. 'I am your fairy godmother and I have come to tell you that you shall go to the ball.'
This story is written in the third person, but if we imagine we are the character of Cinderella we can write an account of what happened that night in the first person (using I and we).
It might begin something like this:
I spent hours getting those awful girls ready to go to the ball and then I had to watch them leave, showing off in their beautiful gowns. It was all so unfair. I felt so unhappy and exhausted that I just sat down by the fire and cried.
Suddenly there was a flash of light. I was terrified. I hid my eyes for a while, and when I opened them again there was a little old lady in front of me, with silvery wings and a wand in her hand.
In this activity, you can practise writing a first person account of a scene from a story that you know well.