Step 5: add a heater if you want to make a useful weapon. Best options are CONV (PLSM) (see ID:1819835 for an example, not made by me) if the weapon will not be exposed to pressure or N-gravity, or subframe ARAY (ID:1781715, also not mine) if it will. URAN, LIFE and VOID with PLSM are all also usable, but take up MUCH more space to get the same level of effectiveness.