Anyone can explain to me about that topic?? Im still newbie, i have learned to much....
You should be able to understand the meaning from the name, it is called private sale because tokens are being sold to private investors instead of the general public.
Privates sales are down by companies that already have investors on ground and don't need funds from other members of the platform while pre sale is a kind of sale of tokens companies carry out before main sales to raise funds for the project before the main sale also referred to as public sale.