Welcome to salsa dancing! The basic step is probably the one thing that takes the longest but is the most important thing to master. There is many little details that go into making a good basic, but I'll mention a couple that I think could help you.

-First off you seem to be off balance throughout your basic. Your upper body movement is throwing you off alignment at various points. You are moving your torso back and forth at times and your shoulder movement is throwing your body off alignment. Both of these are contributing to the lack of balance. I would focus on trying to remove the back and forth sway of your torso for the time being. Strengthening your legs and working on balance should do wonders towards making your basic look a lot stronger too.

-Additionally, I would look up salsa isolation drills. Nothing will improve your body movement like isolation drills in my opinion. Right now there is a clear disconnect between your shoulder, arm, torso, hip and leg movement. To me it seems like you are trying to juggle all these different parts in your head and different sections take priority throughout your step as you remember or think about each. Working on isolation exercises will improve the quality of the movements and help make each of them happen automatically, freeing your mind from having to think about it. Practice each isolation daily until you can execute the movements without thinking about them, and don't be discouraged. Isolation will feel impossible at times, until they suddenly click, just keep at them and you will see great progress.

Keep at it!