Hi Jess - welcome to the NAP club
I'm no expert but you would generally perform "The New Avatar Power Ritual" (P.42) followed by the "Central Pillar ritual" which does consist of all 3 of the steps you mentioned (Opening the power gates, Circulation Ritual and Fountain Ritual).
Below listed is my general NAP outline (this is personal to the way I work and has a few bits added that is different to the outline in the book - but hopefully it might give you a better understanding of the layout I use).
1. Qaballistic Cross + Lesser Banishing Ritual of the Pentagram + Uncrossing Ritual (p.79) [to consecrate the area]
2. The New Avatar Power Ritual (p.42) [to get into the appropriate magickal frame of mind]
3. Middle Pillar Exercise/Central Pillar Ritual (All three steps) [to open and build energy]
4. Invocation to Strengthen the Fountain/Bornless Ritual (p.142)
5. Chants/Incantations etc
6. Licence to Depart (My own transliteration from the Goetia)
7. Repeat step 1 to close.
I also work in the relevant planetary hour for the spirits being called (even though all the extra stuff isn't needed and the original layout is potent enough as it is) - I tend to do this more out of force of habit.
"Be on your guard against all who are subordinate to you ... Trust no brother, know no friend, make no intimates."