Well it is quite a few years since I needed to adjust mine, but in general you centre the swivelling part (black handle) until it is centred, then lock it in place.
Then using a very accurate engineers level, you adjust the lens carriage by loosening the two black bolts directly under the black handle, to align left to right with the head.
Once you have done that, the two alloy looking screws on either side at the bottom, are moved in or out to complete the alignment in the fore and aft mode.
I have the Salt Hill Alignment tool, which is something I should have purchased decades earlier, this is really terrific in getting alignment.
After you have done that, the baseboard needs alignment, that is assuming it is mounted like the De Vere baseboard.
Now I'm sort of going a lot on memory here, but I think that is roughly it for the De Vere.
Any chance of some more inclusive pictures of your De Vere clone enlarger, I've never heard of them?
