almost done and no instructions? to me that means you have not even started yet.
you need to make a list of instructions you want and assign unique code to each of them.
then you build decoder and use it to control the core.
Agree with panic mode. The first step is to define the instruction set. Then create the hardware to decode those instructions.
I would take a look at commercial micros for ideas on the instruction set. I would take no more than then of the elemental instructions only...........i.e. add register to acummulator.