After 3 months I still havn't done much lab work as my lab supervisor and I are optimising new equipment. Recently I spoke to my main supervisor about this and he suggested in the meantime I can use something similar to learn techniques. Now I'm kicking myself for not seeing him sooner. I feel like I've wasted my time doing nothing. Is this my fault? Should my lab supervisor have told me about this himself? I thought it was usual to be spending your 1st few months reading around the subject and doing very little lab work.

Hey stop kicking yourself and learn the techniques. Don't worry about it your only three moths ito it. Many students write up their thesis with the work done in the last year of their PhD, so you have plenty of time. Time spent reading is never waisted. You'll wish to have more time to read once you are into the practical experiments.