The plan starts with setting a goal. How thick do you want the trunk to be, how big do you want the tree (depends on how small you get the needles)? I'm not familiar with the species but i suspect backbudding will be medium.
year 1 Select and wire branches (keepers and runners). Use the lowest growth possible for the first branch. Bend it down in an acute angle and add movement. Examine the rest of the trunkline, wire and place a new top. Let a branch near the top grow as a sacrifice. Remove wire when growing in.
year 2 rootprune, determine rootbase and flare, transplant to ground or big growbox. Keep definitive branches in check, let runners run, remove lowest branches and foliage on the runners so you don't shade the definitive branches. Only remove runners after they done the job or if they create problems.
year 3 Fast growing, idem as year 2
year 4 transplant with rootpruning in a container or smaller training box. Style the tree (if your intention is to develop new runners, start selecting them)
year 5 style tree, decide if runners are needed to restart the thickening process.
year 6-7 back in ground or big box
year 8-9 back in pot.
Repeat until you have a good starting plant (pre-bonsai) i.e. Good roots, good trunk with movement and taper, branches on the right places.
year 10+ start bonsai development.
Most "ordinary" plants need 5 to 15 year of training before you can make a bonsai (worth showing) out of it. The well prepared material comes with a pricetag, or you prepare it yourself (often better, cheaper and you learn more).
It is good to start with material like this, know that only 1 or 2 of started young material will make a decent tree in the long run if you are good. Besides having material like this it is good to have more advanced stock on the bench so you can ease your bonsai hunger in the years you wait for the plants to mature.
side-note: since this will be a project on the long run: look around and determine if this is a plant that
a) produces great bonsai (look for examples you admire)
b) grows vigorously in your climate
c) thickens and matures (bark) rather fast.
PS. you removed the lowest growth. Not often the best choice early in the development.