In the manual for Bookmark+ it says:
A function bookmark simply invokes some function — any function. You can, for instance, define a window or frame configuration and record the configuration as a bookmark. Then jump to the bookmark to switch contexts. (You can also bookmark a desktop and jump to that.)
Which is fine, but I'm not sure how to go about defining my window config.
Ideally I would like it so I can easily just bookmark a window layout. I would press a command, it would ask me for a name, and then bookmark my window configuration.