If you have 64bit cpu you won't need a 32bit OS like Z15.3 Lite, so ignore that. Just test your cpu using cpu-z as I suggested to make sure it is 64bit, then go for Z16.3.
I also suggest you read this pre-installation advice: Before you install
If you have 64bit cpu you won't need a 32bit OS like Z15.3 Lite, so ignore that. Just test your cpu using cpu-z as I suggested to make sure it is 64bit, then go for Z16.3.
I also suggest you read this pre-installation advice: Before you install