for me vs to me
I read this grammar on grammar sites, but still can't understand, what are the differences between for me and to me.
Here are some example sentences:
1. I tried to play chess, but it is very difficult to me,
I tried to play chess, but it is very difficult for me;
2. The grammar exam is hard to me to pass,
The grammar exam is hard for me to pass;
3. It is hard/difficult to me to understand what she is saying,
It is hard/difficult for me to understand what she is saying.
I can't understand what form to chose in these sentences. In my opinion they are all correct and interchangable, but I also know that there are differences between forms "for me" and "to me". Can you please explain me what is the difference? If possible, can you please correct them?
Thank you!