Hi
Is the baby sitter coming to your home? Or are you bringing your lo to the sitter's? Is your lo the only one in the sitter's care, or are there other children?
I think the easiest thing would be to write out a general routine for the sitter to follow (including what you do for wind down, etc) and ask them to write out what his day actually looked like. Like a chart, maybe?
Hth!