In my main gallery page (carbon theme) at the left upper corner, it says "This is the main page of your gallery"
I noticed that other users have put there introduction or some sort instead of this comment....
How do I change this????
Search for "remove this is the main page of your gallery" on Google.
The main gallery page is your root album, just edit it like any other album.
FlashYourWeb and Your Gallery with The E2 XML Media Player for Gallery2
Here's a good link to read up on: http://codex.gallery2.org/Gallery2:Quick_Start_Guide.
Summarises the main aspects of using G2. (now) Touches on this in http://codex.gallery2.org/Gallery2:Quick_Start_Guide#Configure_the_Root_Album