If I say " I enjoy going out with my friend" is the same that I say: " I enjoy to go out with my Friend. I never know when I use " to ( verb) or verb+ing. Please help me

Its just one of those Colloquialisms or nuances in the Language, all languages have them. " I enjoy to go out with my friends" doesn't sound right, it sounds like your native tongue is trying to take over. It may take a long time but it's all about getting use to the language. I hope this helps in some way but I'm no grammar expert.

Thanks, BlueOcean,
You reallly helped me a lot. I'll continue studying to get to know the time to use the terms correctly.

I'm not a grammar expert either, but to me an -ing-form sometimes has the function of a noun in a general sense, rather than a verb. Example: "Reading is good for you" (you can substitue "reading" for any noun). And depending on its place in the sentence, it can be subject or object - in this case, "going out with my friend" becomes a whole unit:

I enjoy... [going out with my friend].

OK! Thanks ,Jeff, for your answer.

http://www.examenglish.com/grammar/like_ing.htm

Maybe this can help you....

I have a complete list of these "verbs of preference".
Feel free to contact me if you are interested ! ;-)

"Enjoy to" is improper grammar. Two options to express this idea are the words "enjoy" and "like".

For "like", you can "like to go out with friends" -or- "like going out with friends".

But for "enjoy", you can only say "enjoy going out with friends".

There is of course a grammar explanation for this, but as Steve says it's just a part of the language you will have to "notice" through lots of reading and listening.

Thanks LFJ ! You helped me, too!

Ok! Thank tou very much, JujuLeCaribou!!!
I'll see the list, and studing them. :)