You are going to have to do some research and testing. WordPress by default, doesn't allow excerpts on pages. The are some plugins that add this feature you can test.
you will then need to search for a way of listing the child page excerpts (do a google search) and then have to impliment the ideas you find.
Please keep us informed of your progress and final solution so others can use it in the future.
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Juggledad | Forum Moderator/Support