very first, before other things, for example, you will do this... (see Molina)
Orthographic Variants:
ocye achtopa, oc ye achtopa
Alonso de Molina:
ocye achtopa. y primeramente, o ante todas cosas. s. hareis esto. &c. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 75r. col. 2. Thanks to Joe Campbell for providing the transcription.