If you prefer to watch videos instead of reading the guide, feel free to do so. There is a video that covers every trophy on my YouTube channel. If you'd like and subscribe or even become a member, it would mean a lot to this channel!
In the first step we play through the tutorial and learn the controls of the game. In this process we'll earn two trophies.
To get every trophy of this part, we need 4 controllers or 3 + 1 using remote play. Winning this race while playing on a track where Giganto appears can unlock a total of 4 trophies in this step.
The Savannah Cup is the first of three championships and at this point the only accessible one for us. Make sure to drift a lot and use boost pads as they are tied to a trophy. Winning the cup unlocks Rugo. All races can be completed on the easiest difficulty.
The Jungle Cup is the second of three championships. Keep drifting to work on Drift over Cretacia and keep winning all the races. Winning the cup unlocks Cror and Totor. All races can be completed on the easiest difficulty.
The Mt. Oblivion Cup is the final championship. Keep drifting to work on Drift over Cretacia if you don't have it at this point and keep winning all the races. Winning the cup automatically unlocks Explorer and Collector. All races can be completed on the easiest difficulty.
The final step towards our new platinum consists of 23 or 24 quick races. 23 if you already won the split-screen race. Every third win unlocks a new skin and we have to unlock a total of 8. The only other trophy that probably hasn't popped until this point is Like a pterodactyl.