I'm here for almost 9 months and I don't know how to change my profile picturee so how do ...

Here ya go http://www.mangago.me/home/photo/9342067/

If your on mobile:
Go to top right corner and press the three lines.
Some options will show.
Press setting.
There you can upload a picture and save it as your profile picture

Thank youuuu (▰˘◡˘▰)