I often hear these mistakes made by German speakers who are learning English.
They say: On Easter I visit my family.
There is a preposition problem here. Remember we use ‘at’ as the preposition for Easter, Christmas, Carnival.
Correction: At Easter I visit my family.
Remember, this means every Easter. It is describing a repeated action or a habit.
Another example could be: At Christmas we go skiing. (Every year the same. Repeated action or habit)
If you talking about a one-off action or something planned for a future date we need to use the _ing form.
E.g. At Easter I’m visiting my family. (It is planned for the next Easter. It is not necessarily the same every year.)
E.g. At Christmas I’m going skiing. (It is planned for the next Christmas. It is not necessarily the same every year.)
Have fun learning English!
Louise