This is the way I do it but there are more experience folks on here that perhaps can give you a better way but this is what I do. First of all I would suggest getting a buffer it makes things go a lot easier, you can do it by hand but from the past experiences a buffer is the way to go.
first of all clean the area first with soap and water, I like to use dawn
dry it off, also make sure you do it in the shade and avoid direct sunlight
this video will show you how to do it with a buffer and then by hand
https://www.youtube.com/watch?v=J5kNFCEPOdU
Hopes this helps and good luck!!