Cgs synth

Hi,

I've made my own PCB for the CGS52 simple wave folder from the
schematic since I got bored at school one lunch. Made it this lunch
and found on the parts list and in the instructions that there are 2
10n decoupling capacitors. The instructions state that there is a
space on the CGS PCB (as in not my own DIY one) for these caps on the
copper side.

Are they needed?

If so, where should I connect them in the circuit?

Thanks,
Finlay Shakespeare