How would you teach fourth grade students how to write an argumentative essay using and citing evidence?

My school will be shifting to using Fundations for our phonics skills next school year. For those of you who have used it with Kindergarten students, what do I need to do to prepare?
My district is not purchasing any materials for us except the teachers manual and online access.

how would you plan a lesson for a standard about an argumentative essay for fourth graders?