Hi,
Those 470 ohm resistors place a hex 0x00 on the data lines so that the uP always executes a 'NOP' instruction. They arent needed if you later connect an EPROM to the data and address lines, which you will have to do at some point.
A good memory mapping technique for a small computer (very small) like this is to use A15 for the RAM/ROM select bit. When A15 is low (a '0') it selects ROM, and when high (a '1') it selects RAM. This maps into 32k of ROM and 32k of RAM but you can use less of each and still use that bit.
You'll have to have some way to program a ROM of some kind, probably EEPROM or UVEPROM whatever you want to use. EEPROM is the more modern.
Once you get some code running in ROM you'll be able to program service calls for various devices like keypads and LEDs and whatever else you want to drive with it like relays, etc. You might find it easiest to interface with a Serial type LCD display rather than an actual monitor at first, as any display type you use should have it's own storage because the on board storage will be so small. You can also map more memory in as pages but that requires more hardware.
In the end you probably wont be able to use this for too much other than small stuff. You can build a small word processor or spreadsheet or whatever but it wont be as good as stuff on the modern PC. You'll probably end up putting it aside at some point but if all you want is some learning experience then it may not be a total loss. After all, the odds of building a modern system from the ground up designing your own motherboard are pretty much very slim because of the complexity of the modern computer.
If you are uncomfortable with the drawing shown, make a new drawing yourself. Put the pins all in a row the way you want to see them and then trace out what each pin has to connect to and draw it. As long as the right pin numbers connect to the required places you're ok.
I sometimes do this myself when i want to make a PC board layout. That way all the pins are in the same place as they are on the actual physical chip.
Back in the 1980's Tandy used the Z80 in their computer, called the TRS80. You can look it up on the web. It had two 5.25 inch floppy drives and a green monitor (green lettering only). You could get a hard drive for it for about 400 dollars and it stored 40 Megabytes of data (yes that is Megabytes not Gigabytes).
In the long run it is probably better to spend the experimenting time working with one of the microcontroller families like the PIC Flash type. You can do a lot with them these days and then you can use them for hardware projects once you become familiar with them.