KDE works on live usb, but not on fresh Install?

I’m sorry but I have difficulties to understand.

Chroot: is “sudo su” and “pacman -Sy cachy-chroot” enough or I have to pass “cachy-chroot” stuff? If it’s the second one, how to I do it? Isn’t my drive have already partitions set after I install CachyOS? And when it says mount additional partition for “/boot”, is it in the same BTRFS partition or in the fat32 partition?

Plymouth: I do “plymouth.enable=0 disablehooks=plymouth” in the konsole when there is a # (not red tho, I don’t know why, at the start of each line it’s "[root@CachyOS /]# "), but it says “command not found”. I did “pacman -Qs plymouth” and I have this:

local/cachyos-plymouth-bootanimation 2-1 (cachyos)
CachyOS Bootanimation (new)
local/plymouth 24.004.60-10.1
Graphical boot splash screen
local/plymouth-kcm 6.4.3-1.1 (plasma)
KCM to manage the Plymouth (Boot) theme

But I don’t know what to do next. I tried this step next, but it says it didn’t find plymouth-git, nor cachyos-plymouth-theme.