Depends on your budget and expectations.How to select rails for your machine
Cheapest is skate bearings rolling on pipe.
Best and most expensive are profile linear rails like THK or Hiwin.
Again, depends on your budget and expectations. It's determined by how fast you want the machine to be, how quick you want it to accelerate, how much weight your moving, and the type of drive system you're using.How to determine what torque motor suits my needs
Since you have zero experience, a kit or ready to run machine may be a better option. What is your budget, and what size machine are you looking for.
For someone wanting to build a machine, with no experience, I'd recommend reasing every build thread here, and everything else you can, for 2-3 months, before you spend ANY money. You need to have a good understanding of how everything works, and what you need.