Here is a great resource for a tech and a good reference for a new engineer. Free Gratis too.
Votes for Real Pars, Tim and Paul.
https://www.ibiblio.org/kuphaldt/socratic/sinst/book/liii\_2v32.pdf
Tony put together a great book (and it's big) He also have good AC /DC electronics material. Play with the URL. Check out All about circuits.. Engineering Toolbox is helpful at times too.
Dead tree book for RSlogic, I am reviewing to add to our onboarding at our office. Seems pretty good so far.
https://www.amazon.com/Learning-RSLogix-5000-Programming-ControlLogix-ebook/dp/B0855XML79/
If you are doing design or need to read P&ID / PFD. Check out
https://www.amazon.com/Instrumentation-Control-Systems-Documentation-Second/dp/1936007517/
PLCdojo is good too. Paul has solid material. https://www.plcdojo.com/collections He has a pretty solid special, 45 bucks for 5 courses.
ISA has some great resources too. Automation Body of Knowledge helped me pass my PE.
https://www.amazon.com/Guide-Automation-Body-Knowledge-Third-ebook/dp/B083JG5KSF/
Look at your vendor sites.. Schneider has some great training, AB if your company pays for support. Check out Forums.. so helpful. Inductive university is solid and they have maker edition of Ignition, free for training at home. Figure out VM's and the if you don't know OT/IT networking. Start googling, google fu is your friend and savior at times. . Youtube has some surprising resources that may or may not be correct. Call Tech support after you have figured out a characterization of the problem. Write that down. Get to know them, you will be calling them. Use your Vendor reps and the training they provide. Sometimes you will get a free lunch but sometimes you get a solution to a problem.
Free advice below, its at least worth what you are paying for it.
Learn to be a self starter and remember you don't need to always KNOW, you just need to know where to find it :)
As questions in groups, not onsey twosey.. make sure it is obvious you have tried to figure it out but need direction after you have FIRST tried.
You WILL make mistakes, learn from them. Try not to repeat them. Own them when you make them and figure out how to fix them.
Take Notes, Use ToDo lists. Figure out a good note system for yourself. That thing you did a week ago is obvious right after you did it.. 12 months ago not so much.
A few more.. no rings on the hands. Single hand in a cabinet until proven unpowered. Be careful where you point and with what you are pointing. Always check your equipment, don't assume somebody turned it off. Learn to love your lockout/tagout on electrical equipment. Disconnects and Estops are there for a reason. ALWAYS CHECK with your meter. DON'T ASSUME. Know your tools and keep track of them. Respect the machines and environment. If you aren't sure, ask. Wear your hard hat, I can't tell you the amount of times I have hit my head in a plant. If you don't feel safe or trained to do the job, stop and tell your supervisor. There is NO place for grab ass on the floor.
When in doubt, go back to first principles. You need continuity and a power source. Check to see if it is wired per the manufacture datasheet /manual. KISS everything first. Keep it Simple Stupid. if that doesn't work, look up and downstream of your problem. Ask what changed and when. Draw diagrams to make sure you understand what you are trying to accomplish..