Present simple
When: Facts, habits
How: Stam (+s; he she it)
I walk to school everyday
?: Do/Does, Am/are/is
X: Don't/Doesn't, NOT
Signal: Everyday, usually, always, etc.
Present continuous
When: It's now going on
How: am/are/is + ing (ww)
I am walking
?: To be begin van de zin + subject + ing
X: Subject + To be + ing
Signal: Right now, now, at the moment, etc.