What modern Kemetic practice has to work with is the opposite of the Heathen problem. The Egyptian material is enormous, continuous and largely written by practitioners. The difficulty is that it describes an institution that cannot be rebuilt.
The concept that holds it together
Maat is order, truth and right relation, personified as a goddess and represented by a feather. It is not a commandment set. It is the condition the cosmos is in when things are as they should be, and it was held to require continuous maintenance: by the king, by the rites, and by ordinary conduct. The negative confession of the Book of the Dead, in which the dead declare the wrongs they have not committed, is the closest thing the tradition has to an ethical list, and it is a declaration rather than a code.
A state cult with no state
Egyptian temple religion was performed by a professional priesthood, in closed sanctuaries, on behalf of a king who was himself a religious office. Ordinary people met it at festivals when the god was carried out, and had their own household practice besides. A modern practitioner can take up the household practice and the ethics with some confidence. The temple cult presupposes a functioning state and a king, and no reconstruction has solved that.
Two approaches
Reconstructionists work from the Egyptological literature and stay close to attested practice. Revivalist bodies, of which Kemetic Orthodoxy is the largest, accept modern revelation and an ordained leadership, and hold that the tradition can develop. Each regards the other's solution as the compromise. The atlas records both without ruling on which is continuous with the ancient religion, because that question is not settled by evidence alone.