Step 3: Nuke it!
Add colouring and scent and stir it in. The amount of colouring will depend on the depth of colour you are trying to achieve - if using clear soap in a white container the colour will seem deeper than it actually is. You will learn what works for you!
Be careful with strong essential oils like peppermint or tea tree, if you use too much they will sting when used on *ehem* sensitive areas. Start with a couple of drops and add more if needed. The soap will have a slightly stronger scent when it is used than when it is molten. Always add your colour first so the soap has a chance to cool slightly before adding essential oils - if the soap is too hot you will simply evaporate them. This also goes for re-melting soap to which you have already added scent, you might need to add a little more.