Essential tools for basic set ups / maintenance?

Crazyblue1779

I would like to be able to (at least on a basic level) be able to adjust action, truss rod, etc on my guitars. 

Just so I can play about with different string gauges / tunings, and do basic maintenance  without having to take my guitar to a tech. 

I only want to do the basics, and I don’t want to spend a fortune, so I’m wondering what are the essential tools that are recommended?

Also is there a specific or well recommended guide or book, or to be a bit more modern , YouTube channel etc?

Any input much appreciated

Cols

‘How to make your electric guitar play great” by Dan Erlewine is the best reference book for learning in detail how to set up a guitar.  

https://www.amazon.co.uk/Make-Your-Electric-Guitar-Great/dp/0879306017/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=&sr=

The Ibanez multitool is pretty good for most things you’ll need to get started (Allen keys, hex wrench, steel rule, screwdrivers)

https://www.amazon.co.uk/Ibanez-MTZ11-Multi-Tool-for-Guitar/dp/B00F4SDYNS/ref=sr_1_1?keywords=Ibanez+guitar+tool&qid=1585403463&s=books&sr=1-1-catcorr

duotone

For setting the action, it also has recommended string action on the rear. 
https://www.stringsdirect.co.uk/accessories-c2/guitar-care-c56/tools-c346/daddario-string-height-gauge-p13806