When I first create it, I duplicate last years version. Then I (or whoever) just adds the names using their editor tool and moves them about manually. The website is ordered, and has the stage for each band, so you can work out the positions from that.
My clashfinder is the Core one for Trees, which means it gets priority and any can edit it up until a few weeks before. Then I can lock it and only give the people who have already edited it permission, as they are basically then trusted.