In thefirst/initial/original place/stage/step;
First = Firstof all = Firstly = initially = originally=To begin
the first stage involves … / in the second stage / in the third stage /
The next step in the stage is that….
After that/at the same time/in the meantime/meanwhile/also
in thelast stage
after aperiod of ..months /days/minutes,
inorder to / in order that; so as to / so that/in preparation for