usama akram

I am new to rails so I have a lot to ask and I find out there is a huge debate on ruby version managers i.e RVM and Rbenv, and there is a bundler too. Now all the articles I have read are old and the more I read about it the more it gets confusing. Now I cannot decide which one is better and which one to use. RVM provides gemsets, but the gemsets take storage space and are difficult to maintain. while on the other hand Rbenv is lightweight but doesn't support gemsets.
I have read that the community moved to use bundler now.
Now the question is how multiple versions and gem dependencies are handled in Rbenv. and how bundler helps in this effect. using Rbenv how can I create a new project of rails with a different version.

it will be a huge help if someone guides me step by step