Turns out this kid was pretty fearless he would play with everything that was shown to him. This kid didn't appear to have any fear at all.
What they then did was have someone behind the child make a loud noise something that would startle him. They did this as they would introduce a white rat that previously Albert tried to play with. What the scientists then did again was to continue doing this up until the point where they found that just introducing the rat without the noise made him cry.
They then introduced a white rabbit to him and found that the rabbit made him cry as well. The fear was generalizing to the whiteness of the rabbit. What the scientists continued to do was introduce stimulus' that were in some form or fashion similar to the white rat every time they found it elicited a similar response from him.