1. (modifier) first, important, large, must, before others - stands before verbs to indicate that the activity is/was/should be carried out first, before some other stated or implied action.
Me mātua hopu koe i te heihei, ka patu ai. / First, you should catch the chook, then kill it.
(Te Kōhure Textbook (Ed. 2): 47-48;)
2. (modifier) firstly, first and foremost, primarily - placed before verbs to indicate what comes first as a priority. This usage is associated with a command.
I runga i te retinga ki ngā Pākehā, me mātua whakapai e aua Pākehā te whenua, arā me turaki ngā rākau, ka tahu ki te ahi, ka rū ki te karaihe, ko tōna tikanga whakapai tēnā (TJ 23/2/1899:2). / With regard to leasing to the Pākehā, firstly they should improve the land, that is, they should clear the trees, burn them and sow with grass; that's what improve means.