Simple Present

For a good lesson, watch this video: 

https://www.youtube.com/watch?v=m28BKjBDafU

You can do some exercises here:

http://www.agendaweb.org/verbs/present_simple-exercises.html

http://www.ego4u.com/en/cram-up/grammar/simpresenple-t/form

http://www.englishmaven.org/HP6/Present%20Tense%20Exercise%209.htm