fpv0 installs on a phone like any other app: an icon on the home screen, full screen, no address bar and no tabs. There is nothing to find in an app store. The install happens in the browser and takes two or three taps. After that all four maps, the race track, the underground garage, the factory floor and the freestyle park, run with no internet at all. Three sets of instructions below, pick yours.
The shortest route. Chrome offers to install it for you.
Use a normal tab. Installing is disabled in private browsing. Tap the Install app button on the home page or on this one.
Open the browser menu, the three dots top right, and pick Install app or Add to Home screen.
Chrome shows the name and icon. Tap Install.
The icon sits with your other apps. It opens full screen, with no address bar.
Open each map once, or tap Save everything for offline in the map list. Together they come to about 1.4 MB, and after that they open with no connection.
Here the install lives in the menu, but the result is the same: an icon and offline maps.
In Samsung Internet it is the three lines in the bottom bar. In most others it is the three dots next to the address bar.
In Samsung Internet it is Add page to, then Home screen. Elsewhere it may read Add to Home screen or Install app. The wording shifts between versions, the meaning does not.
The icon goes where your other apps go. Then fly each map once so they are stored on the phone.
iOS has no Install button at all. You go through Share.
The square with an arrow: at the bottom of the screen on iPhone, in the top toolbar on iPad. If the iPhone bar is hidden, pull the page down and it comes back.
It sits below the row of apps, so scroll the list a little.
Keep the name or shorten it. It launches full screen. Once you have opened each map once, they work with no connection.
Four things worth the two taps.
If yours is not here, the answer is almost certainly yes, it is free, and no, you need nothing.