In case you've not done the YouTube thing here's a link to a how to get behind the door panel/s for a basic speaker change out.:
Another on actual Kicker 6x9 install to a non-Alpine set up. Note: he does mention that the new Kickers bottom in the OEM install wells and leave a gap...but he's not as **** as some about that sort of thing...at least not like I would be.
As far as which hardware to purchase...the skies the limit. Amazon of course will have loads of stuff, but you might like one of my fav outlest...Sonic Electronic's. You can do a rather indepth by vehicle search for what fits and what don't. Here's yet another link to Sonic which might show (if the link works) some 2018 RAM choices for 6x9's.
https://www.sonicelectronix.com/cat_i30_6x9-speakers.html
If your more adventureous you might also like to go with 6" Component speakers in the front doors and 6x9's in the rears. This install with the included 6x9 install adapter plate allows you to move the larger magnet off center to perhaps clear the hardware on the interior of the front doors. Just something to consider. Here's a link to one such package, as an example.
https://www.sonicelectronix.com/ite...ier-6-Component-and-6x9-Coaxial-Speakers.html
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