Help! I am failing at Oil Bath Air filter

[Big_Guys_baby]

I have done a search of this forum and others but I can't seem to find a straight answer. I have a 1946 Business Coupe (my dad's car, but he recently passed away and I am taking up the project) and I tried getting the oil bath air filter ready today but it became a big mess.

how much oil goes in and how do I actually put the oil in? When I tried putting oil in, it went everywhere. VERY nervous about putting it on the carb with oil dripping out of it!