Automate Allen Bradley LOGIX 5555 hardware and communications guide

Hello all
This Is my very first post in this forum, all i used to do is read and i have been so thankfull.
In my new job in oil and gas industry ,we have 8 eight APIs , so it is a must to learn about Allen Bradley Automation and communication.
To be honest i have no idea what should i start first ( hardware or software programing), I chosed hardware because i see software is for an experienced engineer !
I'm posting now seeking your guide ,so guide me for an online course, youtube channel, a simplified lectures .
im interested in knowing generalities and not so deep details at first :

a) Each one of allen bradley modules (analog input, controlnet, relay output, DC output, DC input, ethernet/ip, control net, SAM, logix5555...etc) role and responsabilities.
b) Communication protocoles and their related cables used for transferring data.

thank you in advance ,and sorry for keeping you so long.
For a first pass, check out Ron Beufort's work:
That's more on the software side. For the hardware, there's a lot of variation in their products. Do you know what you'll be working with? Specifically which PLC family?
Ok, that's the ControlLogix 1756-L55xxx CPU. Look for AB publication 1756-UM001, rev G or so. I'm not sure what rev of the manual stopped covering the L55 series. I have Rev G in PDF but it's too big to attach here. I found this link, but I don't know how long it'll be alive:

That'll help you understand the hardware system. You can then search Rockwell's website for manuals and datasheets covering specific modules that you have. That will get you a LOT of information. Do you have a copy of the PLC program? It'll be a file with an ACD extension.
I started learning each module datasheet, then i concluded reading a 100 page for each module ain't a solution for a beginner,,,,,, what i need from you is a guide, and the short not the long way.
Hope you advice me with YouTube channel or series of online courses,,,,,,, after that i will search for the software part,,,, thank you for your time sir
I'm afraid that there really isn't a short way. I don't read datasheets generally until there's something specific I need to know, like how to wire it, its response time, ambient temperature ratings, etc. And none of it makes sense without having a solid understanding of at least basic electrical/electronics theory and practice.

Check out the "EDUCATION" section of this site:
There are resources there that can help you get started on more general stuff. Other than that, I'd say consult the datasheets/manuals specific to your hardware to answer specific questions you have. Look at the software to see what's going on in the system and refer to the documents to figure out stuff that doesn't fully make sense. Look at the drawings and P&ID for your system and use the datasheets/manuals to figure out anything that doesn't make sense. Like, why did they put a jumper there, or why did they ground this one and not that one or why is there an unexpected fuse there, you get the idea.

After the basics, most of what I've learned over the years has been by trying to figure out why something isn't working as expected and then trying to remember that for next time something weird happens.

Sorry, but there aren't a lot of shortcuts in this line of work.
Exactly, that what i wanted to say, i don't want to go for a deep details that i dont need, and when a problem occurs in a specific module or circuit in this case going to details could help.
As i said in my question im still beginner, and have no idea what each module does or role in general ie :like someone explaining in few words (I don't mean each cable tag or instrument wired to it), i really find it useless for a beginner to type each module reference and download its datasheet while there is a general description.