A church order is any work that primarily lays down the practices of whatever church in which the work originated. The largest of these that I will be dealing with here is The Apostolic Constitutions, which is actually a compilation of several older church orders, including (so far as we know) The Apostolic Tradition of Hippolytus of Rome, The Didache, The Didascalia, The Apostolic Canons, and a certain number of prayers which may have their origins in the Hellenistic synagogue. There are also, apparently, clear ties to the Clementine Liturgy.
Once my translation of the complete Apostolic Constitutions is complete, I intend to present here a color-coded version indicating the various sources mentioned above, as well as the work of the editor of the Apostolic Constitutions.
The Didascalia Apostolorum