By over turning I mean that the ends of the wooden blank are turned so that they are slightly smaller than the kit components. If you run your finger over the join you will feel a gap or step.
We all have to learn, your technique and results will improve with practice. The problem with YouTube is there is a much bad advice there as good. Maybe someone near you could give you some help.
I am glad you found my comments useful. I do think it would help beginners if more of our experienced members were prepared to offer constructive criticism rather than just saying "nice pen" when there are clearly things that need improvement.