Simple.
I like to walk. I go to school 5 days a week. My friends eat pizza every day. My brother swims very well. I can cook omelet.
continuous
I'm walking to school with my friends right now. My brother is cleaning his room. My mother is cooking dinner. please wait, I'm thinking. That dog is running really fast.
perfect
he has gone to school. I have already finished my homework. My mother has arrived from work. My father has come back from his trip. I have already Fed my dog.