A lut that normally is meant to be used on an image that is pretty much already ‘done’, means it goes after filmic (so above it in the list of active modules 
). This is also the default order now IIRC .
I have a (hald) lut i sometimes use, that has a subtle warming / saturation effect. I apply it after filmic and any other modules (so basically just before the output module ).
Luts that are meant to be used on more linear data, can be used before . But those luts are rare, and will destroy any data over 1.0 generally speaking. (So exposure can’t be too high before applying the lut. After the lut is applied it can be raised more if you want ).