A couple of comments: 1) When I turn my key on, the speedometer lights do not flicker like yours in the video. When your speedometer lights flicker like yours, that is an indication (on the Symba) that the battery needs to be charged. Your engine is not turning over fast enough to start, and like others have said, when the battery is that weak, even using the kick starter it will probably not start. 2) Once you get a good battery again, and before you try starting it again, remove your spark plug and make sure it isn't dirty, wet or fouled out. Maybe just replace it while you've got it out.
For future reference, after you get it running again, and next time it starts running crappy again, realize that it is rarely necessary to remove, disassemble and clean the entire carburetor. However, it is in fact often necessary to remove the two carburetor jets for cleaning, which can be done on the bike, without removing the entire carburetor. About once a year, especially after it has sat for the winter, I will usually remove the two jets and clean and replace. I like to use carburetor cleaner and a guitar string (wire) of an appropriate size to clean the tiny holes in the jets. But do this very carefully as you do not want to change or damage those tiny little holes in any way.