A guide for a basic setup would be helpful

[FrostKnight]

like I put this in my .bash_profile for startx

GNU nano 5.2 .bash_profile

~/.bash_profile

[[ -f ~/.bashrc ]] && . ~/.bashrc
startx && exit

and then it boots if I have an .xinitrc file with just an uncommented line of the window manager I desire to start.

Like this:

#!/bin/sh

~/.xinitrc

Executed by startx (run your window manager from here)

jwm

How would I do this for sx?

[Earnestly]

sx jwm

The manual covers the example of using an exiting .xinitrc.

Note, that if startx works for you there's no need to change your setup. sx is just more opinionated.