Since you don’t own the apartment, and don’t really seem to know what your doing, I would hire a professional to do it correctly. Explain you have the tile already, you just need someone to install it. For one room it really won’t cost too much (a few hundred dollars), and if you mess up doing it yourself, you will probably have to hire someone to come in and fix it which will be more than hiring someone to do it the right way in the first place. Perhaps if the owner knows how, and your pretty friendly with them, he/she can help you out.

You forget also, that some of the tiles will have to be cut to properly fit the room, and without the proper equipment, how are you going to do that?

You ll need to determine what type of base they used for the marble , such as cement board,mud job or even a wood base ( I ve seen it done).

As well as the thickness that was used. This being if your not over a cement ( slab) floor of course. )
After that a few things you ll need is white thin set, trowels, wet saw, levels, straight edges, buckets , sponges, marble sealer , grout and a helper.
Any questions you can e mail me through my avatar and check my qualifications t GL