The simple present is the tense you use for any habitual action. Use it for things that you always do, are regular or true.
Example: I clean my room every day.
The present progressive tense is for anything that is happening right now. Progressive tense verbs end with "-ing" and have a helping verb ("to be" verb, in the present tense). We can also use it to talk about temporary actions, trends and things that are happening these days.
Example: I am watching a great TV series.
The present continuous tense is used for things that are happening right now or for things that are happening nowadays.
Examples: I am taking a shower right now. Many people are losing their jobs nowadays.
The present perfect tense indicates either that an action was completed (finished or "perfected") at some point in the past or that the action extends to the present:
Example: I have walked two miles already (but I'm still walking).