By playing in a syndicate, you give yourself a much increased chance of winning. For example if you play in a syndicate that has 30 entries into a lottery, the chances of winning are 30 times higher, than if you bought a single ticket. The only difference is that you then share the prize equally with the other members of your group.
A syndicate is made up of shares, each share you buy gives you one part of the prize any syndicate wins, so the more shares you own, the bigger your potential share of any winnings.
In a Lottowinnow.com syndicate there are no more than 120 people in a syndicate group. So you will be playing with no more than 120 people at any time.