Really great question @Mary25 and I think @MeganB did a fantastic job with her answer- there’s not much more I have to say about this that she didn’t already explain beautifully!
It sounds like the author has a template here that resembles the famous WOOP mental strategy (I first learned about it in a university psychology class- it’s a self-help route people can use to fulfill wishes, based on psychology).
I think her structure here is a good one, and I also like the WOOP strategy, but that doesn’t mean that either of these are the only correct way to manifest wishes/set intentions.
Megan worded it perfectly and I can’t agree enough- anytime anyone says that their way is the only right way to do something it should raise a red flag 
Whether its psychology, New Age beliefs, witchcraft, spirituality, etc- there are so many ways (and so many ways to combine them!) and I think there’s a lot of benefit in people trying different things to find what works best for them and their unique practice 
When I set my intentions, I usually mix together a few strategies- I don’t run down a checklist or do things in a specific order so much as follow my intuition to do what feels right in the moment.
That being said, I do usually start with grounding and/or meditating- trying to put daily worries and concerns aside so I can focus all of my energy and attention on the spell. When I feel I’m in a good place mentally, I state the goal of the spell in words (either out loud or mentally).
I wrote a bit about how I like to state the goal/intention itself and it turned into a book (oops!), so I actually moved that into a different discussion to avoid veering this discussion off-topic 
But basically, I state the goal/intention/direction of the spell to some level of specificity (either out loud or mentally). I also try to repeat it several times through the spell (mostly to help keep me focused and present- my mind likes to wander off 
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And then I let the magic take over- letting my visualized/stated wish be carried out and allowing the properties of the ingredients in the spell spark to life as I call upon them.
Again, just a rough idea of how I usually approach spells- while there are similarities to the checklist above, it does differ and it leaves a lot of room for adjusting to the current spell/moment/situation! That’s how I like to do things in my practice, but I always love to hear about other strategies and observe how others set their intentions
Thanks so much for opening this discussion, Mary- it’s a really insightful one! 