Virtual Machines Setup for dev/test/prod landscape

Hi Experts,

I am new to this area and had one query on the virtualisation criteria. In the website, we do see the general set of parameters stated for cpu cores, hdd based on number of robots that would run. But can someone please advise on the setup of VM’s per landscape (considering on prem setup) and is there any general set of recommendations that one should take care of?
Thanks,
Saritha