My first Amiga 4000, how to install Amiga OS?

[SACC-guy]

I made an OS3.9 emergency adf with fat95 and diskimage.device, quite convenient

All well and good.
This does not help the OP, he messed up his working system and doesn't appear to know how to fix it.

We can help, but it might be better if he goes back to the person who sold him the 4000 to get the "things" and info he needs to move forward.

[LoadWB]

I have made a generic EBD, and there is enough room on the disk to put several CD0: devices, depending upon the various SCSI devices I may be using: scsi.device, cybppc.device, etc., and only uses LoRes mode which can be changed upon boot.