Dear Rahul

There are many YouTube channel these days that tends to provide free video tutorials to students nationwide. It seems to me that your choice of interest is SSC CGL. For that I would suggest you

Rajesh Sharma solutions

They solve each and every question from Rakesh Sharma quantitative aptitude book. To clear any exam requires lots of practice so it is wise to use videos only to take a hint or when you are stuck in some topic. Self practice is the key.

Good luck