There are plenty of guides on the internet about NFS. Still it took me ~2 hour and 15 different website to get NFS working on my home server. The reason? Well firstly, a lot of NFS posts are outdated because of a switch from portmap to rpcbind. Secondly, NFS was never properly installed. Because NFS is part of the kernel the nfs-kernel-server and nfs-common files can still be on the system even without the packages being installed.
The best source I found to setup NFS on debian is: http://debian-handbook.info/browse/stable/sect.nfs-file-server.html