As for sorting the works in the Masonry layout, the Bild theme obeys the general WordPress logics and sorts posts (portfolio projects, gallery posts, etc.) by date. So you can assign the dates to the projects so that they are sorted the way you’d like them to be. You can also use a third-party plugin for that. G.g. this one. Given the number of projects you have, I’d go the manual way with the dates.
Also, please mind that Masonry has its own logics of sorting that lets it fill the space in the most efficient way. So when using Masonry you will not have full control over the placement of the items due to the nature of Masonry.