To progress to a situation where I can write programs for the computer, I need to add RAM. Without any RAM, my programs would not be able to use

The RAM will use the address space from $0000 – $3FFF. The reason for this is because I will need to use zero page for my programs. The zero page is the first 256 bytes, which is $0000 – $00FF. This RAM needs this zero page to pre and post indexing.

I will also need my RAM to use page one to run my programs this is from $0100 – $01FF. This is because the hardware stack uses page 1 and will be needed for operations such as interrupts and subroutines.

Now I should be able to write programs that can write on my computer.