Make sure you pick the right blend for shade.  Hewitt’s Super Shady Blend is made of grass types that thrive with no direct sun at all.  Here’s a link on how to get the seed started.  Once it is established, it should be pretty self-sufficient.  If it is growing under a shallow rooted tree like a Maple tree, it may need some extra watering during the hot part of summer since the tree will be hogging so much of the moisture from the soil