DalamudPluginRepo VS Penumbra

You need to do this.

XIVLauncher has most of the main plugins and if you add this repository you can browse all the ones that aren't supported by XIVLauncher due to its rules too

If you already have Dalamud, there's installation instructions here. It only takes a minute or two. Once you have the custom repository set up in Dalamud, the plugin "Cammy" should show up, you can install it and start messing with camera settings in its menu.

Then just follow the steps on the developer's Github

with dalamud it's just following this https://github.com/UnknownX7/DalamudPluginRepo , installing "ReAction" and clicking "Enable FPS Alignment" under Other Settings

Do NOT follow the instructions on https://github.com/UnknownX7/DalamudPluginRepo to add the third-party repo to your dalamud and add reaction to your plugin list because that is against the rules and will make yoshi P sad

https://github.com/UnknownX7/DalamudPluginRepo here

It's a third party plugin for XIVLauncher; you can access it and all of UnknownX7's other plugins by following the instructions here. It has a bunch of combat QoL, but arguably its most important feature is one that forces a frame to render as your GCD rolls, which normalizes your GCD. It's really helpful for Monk, as to be really 100% optimal you either have to use it or lock your FPS by hand.

you need penumbra if you don't have it yet and use that to install the mod

You can find various body edits on https://www.xivmodarchive.com/ . In order to use them, the easiest way is to use the XIVLauncher (https://github.com/goatcorp/FFXIVQuickLauncher) which enables the addon system. With that, download the addon "Penumbra" to use those edited bodies ingame (https://github.com/xivdev/Penumbra).

Runtime loader (Custom clothes, animation): https://github.com/xivdev/Penumbra (a year old)

You'll need Penumbra, which in itself requires Dalamud ala the FFXIVQuickLauncher tool. You can install FFXIVQuickLauncher via an installer and here's a video for installing Penumbra.

Download that, also download textools https://www.ffxiv-textools.net/ OR penumbra https://github.com/xivdev/Penumbra (this one also needs XIVLauncher) and then import the file you downloaded from nexusmods, and that's it.

Penumbra

Penumbra is a quicklauncher plugin (link) that allows you to non-destructively apply mods.

From what I understand that was fixed a few versions ago. https://github.com/xivdev/Penumbra/releases/tag/0.4.6.7

Should be this one I think.