Pedal up to about 10mph, slowly release the clutch lever.
Trying to engage the clutch too soon is the most common problem people have, especially those who have never driven a manual transmission automobile.
It needs to be a coordinated movement that will come with some time and experience.
Don't try to engage the clutch too soon or at too low of a speed. That will smooth things out for you. Practice, practice, them practice some more. You'll get it eventually.
Tom