Newbie Question about Motherboard Installation

I admit I'm a novice, so all help is appreciated.

For building the computer, is it better to first assemble everything to the motherboard (X570 Phantom Gaming X) and then install, or is it better to install the motherboard right out of the box into the computer case (Lian Li 011 Razer) and then install the rest of the items?

I'm thinking I'd set the case on the side, install the motherboard, and then start installing everything else. It seemed that long ago with a computer I built that the motherboard tray came out of the case, but it doesn't seem to be removable now with this Lian Li case.

I would install the CPU with cooler and it's fan, the RAM and the GPU and place it on the desk. Connect the PSU, Monitor and test, if you can go to the bios, loading defaults and restart. Then switch off, unplug the PSU and install the drive (M2 or SATA HDD), where you want to place your OS.

After the installation and checks, if everything runs OK, shut down and unplug the PSU.

Remove the GPU and HDD (if you use no M2) and install the board in the case. Then move on with the rest.

Believe me, if there will be problems with the setup/installation, it is more easy to deal with as if everything is in the case and nothing works...

Thank you very much for the helpful suggestions.

I had been thinking along similar lines regarding installing the CPU prior to installing in the case. I was debating then about when the heatsink/fan should be attached, I'm not sure how difficult it is once in the case.

I hadn't thought of installing the ram, but I'll do that too.

I just wonder if there are any "gotchas" that I should be watching out for. I've already put the power supply in, and then took it back out and attached all the wiring for it, since it seemed pretty difficult to do once installed.

Does anybody put the power supply in the top slot instead of at the bottom slot?

Thanks again.