Three details on top of the basic pattern laid out earlier will help you handle the comings and goings of the /e/.

(a)    The /e/ vowel actually comes up as /a/ when it’s followed by /q/.  Otherwise the pattern is the same.

naqa’si                    I stop
→    ‘nqa’si                    stop!
→    ‘npa’sites                I will stop

naqalg                        I leave h/her
→    ‘nqal                    leave h/her!
→    ‘nqalates                I will leave h/her

maqtawe’g                s/he/it is black
→    ‘mqatawapu            “black-broth” = cormorant

(b)    Because /o/ is generally originally from /a/—give or take some other details—a few words have the same pattern with /o/.  The most common and useful of these is /poqt-/ ~ /’pqot/ ‘start, begin to…’.

poqtlugwei                    I start working
→    ‘pqotlugwa                start working!
→    ‘pqotlugwetes            I will start working

(c)    Finally, a few words have a slightly quirky pattern between the e-form and the plain form.  The most important of these is /wejgu-/ ~ /jugu-/ ‘coming this way/here’.

wejgu’ei                        I am coming (here)
→    jugu’a                        come (here)!
→    jugu’ates                    I will come (here)

wejgua’tu                        I am bringing it (here)
→    jugua’tu                    bring it (here)!
→    jugua’tutes                I will bring it (here)        (also said /juguattes/)