That's really all you need to know about how to play footgolf: It's exactly the same as golf in most ways - you start play from the teeing ground, propel your ball down the fairway, toward a green, and into a hole; it uses golf rules and can be played on either a real golf course (with much larger holes cut on or adjacent to the greens) or a purpose-built course. The larger cups are obviously needed to accommodate a soccer ball.
The website of the American FootGolf League says this about it sports' genesis:
FootGolf does not "compete" with Golf. FootGolf does not "compete" with Soccer. FootGolf can be as fun or as competitive as you want.
FootGolf is a game on its own and it has been played since forever around the world in farms, parks or streets, under different names and rules. As a sport, it is played on golf courses and is regulated worldwide by the FIFG. The first tournament was organized in Europe in 2009 and it was introduced in North America by the American FootGolf League in 2011.
As of today, the American FootGolf League has established and accredited 66 FootGolf Courses throughout the Continent.
The AFGL pitches footgolf as a second income source for traditional golf courses, noting that the 21-inch cups can be cut in areas of rough adjacent to the regulation golf green, rather than on the green itself. That saves golf courses from having to close holes to golfers in order to accommodate footgolfers.
A map on the AFGL website shows there are currently 60 golf courses in the United States that allow footgolf, three in Canada, two in Mexico and one in Puerto Rico.
The world footgolf governing body - FIFG (Federation for International FootGolf) - was established only 2012. FIFG shows that footgolf is represented by country organizations such as the AFGL throughout western Europe and also in Australia, South Africa and some South American countries.
In other words, footgolf is a very young sport that is already surprisingly available, and is already - surprisingly - having some success in getting traditional golf courses to set up footgolf "cups" on or next to their greens.
Here's a Trans World Sport report on footgolf:
The advantage to footgolf is obvious: It requires nothing but a soccer ball. That makes it much more affordable than real golf to play. Things like this make me wonder if the real threat to traditional golf is not from competing sports or unrelated activities, but rather from alternate versions of golf itself.