Getting started

It takes a little to get the emulator up and running. All directories are relative to the folder with the settings.ini file in it (automatically created together with the folders when starting the emulator for the first time).

If you're having trouble clicking the yellow text or pressing the Select button (PSP(-style) input), you can modify the firstrun setting in settings.ini to 1 to open the settings menu automatically once when starting the emulator. Both clicking/tapping the yellow text and the Set button in the bottom-right corner open the settings menu. Some settings are locked when emulation is started (once the yellow text disappears), but rebooting the emulator by restarting it or using the settings menu option for that will restart the entire emulator, causing the yellow text to appear again for setting up the rebooted emulator. It's much like a mini-BIOS in that regard (although it's a BIOS that bootstraps the actual BIOS).

1. Start the emulator once and close it(after the basic setup of the system) to create a directory structure and initial settings.ini file. Setup the video card, architecture and CPU as required by the emulated system before closing it. The empty 8KB hard disk image from steps 4/5 can also be createn during this step by using said option in the disks menu.
2. When using the server build or non-server build with custom modem settings, adjust the modem section in the settings.ini using a plain text editor. Besides a non-default TCP port for the serial modem to listen to or dial out with or setting up the server build's modem to use as a internet server, this step is optional.
3. Create a ROM directory (if not createn yet, case sensitive) and put the required BIOS ROMs in said folder, according to the explanation on Settings menu's description of the execution mode Boot with BIOS ROMS, as well as it's section on Other ROMs.
4. Create an empty ROM file for flashing (see Disk images' XT-IDE Universal BIOS Configurator section) and flash said XT-IDE Universal BIOS ROM from a bootable 360K floppy disk image containing the files from the website. A simple MS-DOS disk with said files added using WinImage will do the trick.
5. Create a Plop Boot ROM for booting CD-ROM disk images(requires a 80386 CPU or newer and Compaq Deskpro 386 and up. i430fx/i440fx don't need it). This is required for the Compaq Deskpro 386(and PS/2 architecture, which is a Compaq Deskpro 386 with PS/2 support added to it) BIOSes to boot from CD-ROMs (See Disk images' CD-ROM booting section).
6. Finally, any empty hard disk or floppy disk images can be createn using the settings menu's disk creation options, except CD-ROMs. Hard disks can be createn anytime, but together with some other settings, cannot be remounted without a full reboot of the emulator (the settings menu does this automatically). This is just like with a real system (not hot swappable). Floppy disks can be createn anytime and together with CD-ROM discs can be reinserted either automatically (floppy disks after creating a disk image) or manually using the settings menu (like with CD-ROMs).

Of course there's still a little thing to do after getting all that ready, which is mainly the configuration of the BIOS itself. This can be done by using a disk image after booting which contains either the configuration software of the BIOS itself(The Compaq Deskpro 386 Diagnostic disks and IBM AT Diagnostic Disks/Setup disks for those two platforms. Simply boot from them) or by simply running gsetup(on AT/Compaq Deskpro 386/PS/2 architectures) from such a MS-DOS floppy disk or hard disk image to configure the CMOS parameters for the BIOS to use. These are pretty much the instructions posted here: 5170 setup. The same pretty much applies to the Compaq Deskpro 386 architecture. The only thing configurable in the XT is the XT-RTC timer, which has a different program to use: it uses a simple PC timer RTC chip which can be used(http://minuszerodegrees.net/rtc/rtc.htm , section [PC TIMER], version 1.2 for the Samtron 88S(which is the chip that's emulated)). The i430fx/i440fx architectures usually can be configured from their POST BIOS menu, usually acrivated by pressing a mentioned key while it's counting memory. Remember to set the primary master/slave to auto for installed hard disks to be detected properly. The CD-ROM drives on the secondary master and slave are setup by setting the setting to CD-ROM instead.

A little note: On the AT 286 6MHz system, the emulation isn't accurate enough to allow the BIOS to boot with it's default settings(it's slightly too slow). To compensate, place a breakpoint at F000:05B8 and adjust the CPU clock speed to make the CX register as close to F952h as possible. Using the current UniPCemu builds, that happens at a speed setting of 4808 cycles. This can be used as a workaround to make the BIOS boot properly.

There's also this tutorial in video format, which can be found here.