I like begin with getting followers and leaders familiar with steps forward, back, left and right. They should be able to lead and follow, and have fundamental technique. A lot of dancing can be done with only those steps, and I want dancers to realize that.
When dancers have some capability/competence with that, hopefully by the second week of class, I introduce simple forward and back ochos. I try to make sure everyone keeps up with good technique.
By the third week, theoretically, I can introduce molinetes, but I'm in no hurry.
Maybe by the fourth week I can introduce cruzadas. IME, followers struggle with this step, because it's not normal to step with their left foot to the right side of their body. Lots of women balk at that initially.
I don't try to get dancers to the milongas as soon as possible. If it takes eight weeks, that's fine with me. Also, I've had students who were reluctant to attend milongas even after I thought they should, in order to continue their growth.