I second Xarmanla's comment. This isn't something you can learn perfectly from an italki answer.

Forget the nonsense taught by most texts that attempt to teach English to foreigners. The "ing" is used on verbs in two distinct situations. The first is the present participle. I am learning English. You may have started to learn English years ago but you are still in the process. Learning is fun. This is an example of the "ing" in a gerund. My advice is to read English grammar books in English or ask a native English speaker.

it is called "present continuos" and it is a suffix that is used when you or someone is doing something but do not stop, keeps it doing for a small period of time, an example would be: I am running - I run but I am still running. it always comes after verb to be. Hope I clarify your question, have nice day! :)