I really like this type of nursery stock, you get to develop the structure from scratch.
Before worrying about anything else, its probably best to go through the process of selecting your front: described very well in: https://live.bonsaimirai.com/archive/video/nursery-stock-series-pt.-3
So find your best base, your best angle of viewing, your best trunkline with most interesting movement…
remember for these little junipers, you can radically alter the trunkline with wiring too, and also, the longest thickest part doesnt have to remain the trunk all along…
It’s well worth thinking about transitioning to a primary branch after the interesting movement of the trunk stops, and then wire the new branch up as your trunk…you can cut off the rest of your old trunk and fashion it as some deadwood.
Just be aware of the season that you do the work in…i’d probably do a good winter of cutting and styling, but leave it to recovery before a repot.
Though saying that, I’ve done both styling/cutting in winter and then repotting in spring for this type of nursery nana and gotten away with it (in UK, so might react differently). Thats not a recommendation, just an observation.
I love these little trees, i’ve done most of my learning about wiring, styling and pruning from these…and also watering and soil…as i’ve killed a few early on too.
Good luck and have fun. You can make a nice looking little tree.