For most homebrewers, sour beer is close to a failed brew, and that is why it is a scary risk. The idea behind a sour beer is that you introduce outside bacteria and wild yeast into your brewing mixture. Because of this, you have to change your whole equipment or face the risk of having all your pale ale become a hopped up lambic.
With wild yeast, patience is crucial. You will need time. Lots of time. You will have to pitch a lambic blend of pedio, brett, and Lacto. These ingredients take time to mature and finish their flavors. You will also need US-05, but only to ensure that your primary fermenter is preserved from contamination.
In brewing, everything is technically normal. The only difference is that in the beer style, it has to be relatively mild. This is because flavors will be more defined by the low finishing gravity of the beer.