A simple enough achievement, but will NOT be available straight away.
Just playing through the game at roughly around 3-4 hours, you will qualify for the Horizon Roster (Which basically means your free to do whatever the hell you want in the game).
3 Unlock once you qualify, and as you earn more influence (Aka go up in levels, which you can earn by smashing bonus boards, doing skill points, partaking in tons of races, basically theres a lot of ways you can earn influence). Once you earn enough, Joel or Kiera or whoever will let you know on the world map whats unlocked next and what you can do.
I've just made some videos of all 5 showcases, locating them on the map and doing the actual races.. Just for fun and just incase theres some parts anyone may get stuck on.
Also, one more thing, you dont havwe to win to get the Achievement, but if you like to win anyway, you wont automatically win, there are times you can come second so jut bare that in mind!
Anyway, hope the videos help and thanks for watching and enjoy! (Any silences in the video means there was audio copyrights unfortunately)
1. The Delta Wing Showcase
2. The Horizon Motorcross Showcase
3. The Flying Scotsman Showcase
4. The Behemoth Showcase
5. The Halo Experience Showcase