Once you added your first project to bookmarks, every time you start working on the project, after opening Vim, you have to select the project in Vim-CtrlSpace. Fortunately all you have to do is pressing:
CTRL+SPACE and then b.
Opening projects in search mode
Capital B opens the project list in the search mode so you can find the project faster.
Alternatively you can open the list of projects with b and then open the search mode with /. The same applies for all lists.
Opening projects in Vim has never been so easy!