Build a visual workflow in Photoshop / Powerpoint

I am looking to create a visual illustration of a workflow for a simple mobile app. We have screenshots of something very similar to what we want to create, so the project would include taking elements from these screenshots and creating new visuals to illustrate our product. Would include changing the colors, adding in a new logo, splicing out specific images from the workflow, etc. We will need 4-5 images and envisioning the output being a powerpoint page with the images dropped in and call-outs around each of the images describing what is happening at each step. Looking for someone who has both some design skills but also some experience building out workflows. Also want someone who is a very strong communicator -- ideally I could give you some direction and you could work within the direction we give to execute on the project.