In general, by step, I think everything is clear, the work is not difficult, but requires a certain skill. Advice:
1 - print directly the size of which will be final for your crafting.
2 - Do not use aerosol paint, corrodes polyester even through primer paint.
3 - for gluing better glue on a rubber base.
4 - I cut with a stationary knife, but this is convenient only in areas requiring extreme accuracy, in other cases, it is better to use an angle grinder.