Hola MB

The imperative needs to be seen not as a whole conjugation because depending on who the imperative is directed to, the ending will vary. Being reflexive or not won't change the ending. For example, for levantarse:

This is the reason why in Kwiziq the lessons related to the affirmative imperative are divided into different subjects. 

Here are our lessons on affirmative imperative. Have a look at the links with the lessons at the bottom, you need those that say "Forming the imperative of/for..." 

Saludos

Inma