If I were using hot water & soap I would disassemble it as far as practical before cleaning. Hot water & soap works fine for cleaning, but I haven't used that method for many years onrifles or shotguns.
First off, the reason for HOT water is to get the metal warm so it will dry quickly. Not really sure why soap is needed or recommended as plain old water is a great PB solvent. It certainly won't hurt, but I never use it anymore.
I use cold water, or one of the commercial BP solvents (T/C # 13, or Butch's BP Bore Shine for example), or a home-made solvent like window cleaner or automotive anti-freeze & water. Plain old water seems to work fine, but some ot the other cleaners are quicker.
The reason I don't use hot water is that I have found by blowing compressed air through the bore will remove most of the moisture, then a dousing with WD-40 (WD = water displacement) and more compressed air & a few clean patches remove the WD-40. Then I can oil the bore to protect if from rust.
The main steps in cleaning are to:
#1 remove ALL trace of BP (or the BP sub powder) residue.
(I also use a bristle brush to remove any plastic or lead residue from the projectile during the process)
#2 remove any moisture step #1 may leave in the barrel.
#3 coat the metal with a rust inhibiting preservative.
Very simple and it works for me!