Getting acceptable white balance can be a real challenge, depending on the circumstances, so don't feel a numpty
There are many ways to skin this cat, but one plugin I use a lot is ColorCast Correction from the Digital Camera Essentials pack ($39/£26.74).
That's for TIFFs, JPEGs etc., but I should think all RAW converters have a white balance tool. RawTherapee is one you can have for free or a donation.
Or are you asking how to set the WB in camera?