Before you build it note that you need an open frame PLCC socket or you need to put C3 on the back of the board (bent to lie flat). Either way you want to solder C3 before you fit the PLCC socket.

It's easier to get the angled headers down first before soldering resistor packs and the chip sockets. The jumpers and PLCC socket are the highest.

For normal use cases jumper JP1  1-2 so that IEI is pulled high and J2 1-2 to put the card at 0x7E. (That's the pin pair nearest the RC2014 connector). The jumpers control which address lines other than A0 must be low (A0 must always be low). Unfitted is high.

JP3 and JP4 connect port 1 to the RC2014 backplane RX/TX for use with things like the PI terminal or the forthcoming Gluino card.

If you are using Z80 IM2 then jumper JP2 and set JP1 2-3 so that IEI/IEO are in the expected chain.