Step 1.) Determine equilibrium lattice constant: loop.job
To make a quick plot of SUMMARY.dia try:

gnuplot

gnuplot> plot "SUMMARY.dia" using ($1):($4) w lp

Step 2.) Enter the correct equilibrium lattice constant in the POSCAR file

Step 3.) Determine the density-of-states: dos.job

Step 4.) Calculate the bandstructure; band.job
N.B.: you need the CHGCAR file from step 3. 
