No software needed. You just plug the USB charger that came with your tablet from tablet to USB port on PC. Then let it install drivers. Your android device will show up in file explorer. You just open the folders to explore files. Its not like an iPhone where you need iTunes. On the nexus 7, In settings/storage in the upper corner there are three dots, tap them. You will see USB computer connection, tick the box that says media device so the box has a check mark in it. That's it.

 

For that you need adb. Or if rooted you can use a custom recovery system installed on the tablet.
But I think your best bet would be wugfresh nexus root toolkit found here
This will install on your computer and will simplify all of those things. I use it all the time. In case of failures the nexus 7 can be repaired using a factory image as well as a backup image. This toolkit does all of that for you as well. It downloads all resources needed to perform its tasks.
Have fun!