The present perfect and simple present are actually two different verb tenses, netxm. There’s no “present perfect simple.” “Present” relates to time, and it can be used with either the “perfect” or the “simple.” The thing that is the same about these two tenses is time: they both take place now (in the present) or are at least related to the present. But the uses of each tense are different.
Here’s an example of the present perfect: I have watched the movie “Titanic” 5 times.
And an example of simple present: I watch movies.
In the present perfect, you should use ‘have or has’ plus the past participle of the verb (watch out for irregular verbs!)
In the simple, you should use the present tense of the verb. No ‘have or has.’
There are some different reasons for using each verb tense. Usually we use the simple tense to talk about facts, people’s habits, and routines. We use the perfect when we want to show that an action started in the past but is still continuing (or is still important in) the present.
So, going back to the examples: When I say “I watch movies,” it just means that movies are one of my hobbies. I watch them every weekend, maybe. It’s a fact about my life.
But the perfect tense is a little more complicated:
When I say “I have watched the movie “Titanic” 5 times,” it means that I first watched Titanic five years ago, and then I watched it a few more times in in the past, but I expect that I will still watch it again. I choose the perfect tense to show that the action (watching Titanic) is still related to right now, even though it started five years ago.
There are more reasons for using the “perfect” instead of the “simple,” but these are the basic rules. Good luck!
Here’s a good website:http://owl.english.purdue.edu/owl/resource/601/01/
Check it out or let me know if you have more questions. :)