I personally think the people that make the best project managers or sales people are those who have worked in the industry for a number of years.
There such a vast number of elements that any project manager or sales person will need to have a good knowledge of to be successful.
Probably the best way to learn is to actually work in the industry or at least shadow your other employees for a few months or at least at specific times when the various different elements of the industry come into play in your business.
Sales people are effectively the first point of contact a customer has with your business, if they don't sound like they know what they are talking about and aren't able to give the right answers and solutions for a specific job, you risk losing the customer entirely or making costly mistakes which is why good experience is crucial.
Sure you can teach the basics regarding different types of vinyl, different substrates, the different manufacturing processes involved etc. etc. but I don't think there is any specific literature for this and I doubt the basics would be anywhere near enough for someone to manage a project.
Perhaps you would be better off delegating these roles to experienced employees and effectively promoting from within the business then employing someone young to learn the industry and gradually take on more responsibility?
^agree with this 100% but also know that's just not how it is going to play out sometimes. If you have to hire "just a warm body" off the street, do your best in the crash course mode (I'd keep it basic, pros/cons of materials, with lots of example jobs), then make it
very clear to them that they do not know everything and they need to get comfortable
asking for help & telling a client "
I will find out about that" or "
let me talk to my team and find the best option for you".
The worst thing you can end up with is someone who has
no idea what they are doing - confidently. Even if they manage to not over-promise something to a client, it will destroy your team morale.
Guides/manuals for training: We've made lots of guides and manuals over the years, they're useful tools but need to be customized per company & if you rely on them too much, people have a tendency to not use their own critical thinking skills (If I just have to fill out this form, do I really need to know what goes into a job?) That said, I would focus on materials you have access to/use regularly - they don't need to know how every sign is made right away (if you have other competent staff), but they do need to know the language to communicate a client's ideas back the rest of your team.