Hi I am messing around with my threadless stem for the first time to rearrange the spacers, flip the stem and lower it a bit. So it seems pretty simple but I just wanted to check here first. I am also going to be doing this with the bike on the ground and not on a workstand. Is it important to keep the wheel still while doing this?
First thing would be to take an allen wrench and undo the top cap on the steerer and take it off.
Loosen (or remove?) the clamp bolts on the stem also take off the face plate to take the handlebars off.
Then rearrange the spacers and flip the stem and put it back on the steerer
Put the top cap back on and tighten and then align the stem with the front wheel.
Tighten the clamp bolts on the stem and then reattach the handle bars

Is this all? any steps out of order?

Looks good. A couple pointers to add:

You don't have to remove the stem pinch bolts, just loosen enough to allow the stem to slide on the steerer.

The top cap bolt sets the headset compression: tight enough so there's no play if you squeeze the front brake and rock the bike back and forth, but not so tight that it binds when rotating the fork left to right. I might put the handlebars on during the headset pre-loading (setting compression) to make it easier to test with the front brake.

Use all the spacers, even if it means you have to put some on top of the stem. If you don't have enough spacers then the top cap will hit the top of the steerer making it impossible to set the preload.

+1, between you and Jive Turkey you have it.

There's no reason to worry about the holding the wheel and fork while working on the floor since gravity will keep it all together. When tightening the topcap to adjust the headset, taker up all the slack then add pressure about 1/8th turn at a time until there's zero detectable play with your fingers at the bottom of the lower bearing, then add maybe 1/16th turn to ensure that the headset is tight.

Finish by aligning the stem and tighten the stem bolts and check that the steering is free through the range.

Hmm what lower bearing are you talking about? Are you talking about that big cap right at the top of the headtube? I just did it, but I'm not sure if I have everything secured and properly put back together...

Also at first I accidentally tightened instead of loosening the clamp bolts of the stem around the carbon steerer... I didn't hear any loud noises so I don't think I cracked it. But there is a bit of a mark shaped like the space between the clamp bolts on the steer tube... hopefully that was just an imprint from the original installation...

do it with the wheel on the ground.. or the fork may fall out of the frame,
the pinch bolts and the top cap is what keeps it together.

I added a "locking spacer" QBP, it sits as the lowest spacer,
it's one pinch bolt holds the fork in, when everything else is loose.

bump

What FB was refering to was to check that there is no play in the headset after you've adjusted it. Put the bike on the ground, lock the front brake and try to move it fore-and-aft. Place your fingers around either the top bearing or bottom bearing and be sure there is no movement there when you thy to move the bike the bike.

If the fork turns freely but there is no headset play, center the stem over the front wheel and tighten the stem bolts to the proper torque.

beginnerbiker1, speaks to an issue.. not thinking about what you are doing before you do it.

(or just admitting that you are not mechanically inclined,
[ no way can specialist, software writing skills, a different set, of overcoming that]
and turning the work over to the folks at the LBS, that are)

The headset has two bearings one at the top of the frame below the stem, one at the bottom where the fork enters. You want to feel for movement between the parts attached at the top of the fork, and the bottom frame.

Given you're lack of familiarity, I strongly suggest you search "adjusting bicycle headset" and read a few tutorials until you have a decent understanding of what you're doing before you fo any further.

I don't see any bear between the frame and the fork if that's what you're asking. I tried holding the front brake and rocking it back and forth and it seems to have normal range of motion. It's an FSA integrated headset if that matters at all. I'll bring it back to the LBS to make sure I did it OK and I didn't damage the carbon steerer when I accidentally overtightened.

You won't see the bearings when the headset is installed. They are hidden inside cups in the headtube and covered by the top cover and crown race but they better be there.