This Trophy is only possible while playing the Online-'Sport'-Mode.
There are 'Daily Races' every 5 to 10 minutes which you can sign up to. For now (at release date), there is a section of three different races (A, B and C) which are held four times per hour each and are about five to fifteen minutes long in total. The three 'Daily Races' usually change to three new ones on Sundays. There will be other tournament-like races in the near future, starting in November 2017.
For this trophy, it is enough 'just' to finish 322 online races. Even if you take the shorter five-minutes-races, this will take you about 30 hours. You probably want to aim for winning 91 games for the aforementioned trophy. Depending on your skill level and luck, even 322 races might be not enough to win that often – so you probably don't have to worry about this trophy, but rather the 91 wins and 65 pole positions.
