Was trying to figure out really what the trial is about but this seems to be a nice guide.
https://ffxiclopedia.fandom.com/wiki/Free_Trial_Guide
Would highly recommend picking up your trusts (fake party members) ASAP. These will allow you to "solo" much more efficiently.
Don't worry about race, its not that big of a deal.
Each nation has its own flavor, I personally like bastok the most and sandy the least.
Your 1 character can switch to any of the unlocked jobs, so not too much reason to try leveling 3 characters. *edit* Actually if you wanted to start each city's story, making a character in each is a viable way. But do not worry if you want to be a taru in Bastok...its allowed and the only thing you miss out on is a easily replaceable/ignorable ring.
A fair warning, many classes can be very boring early. Mostly the melee classes are snooze fests. Most abilities have very long cool downs and instead were given much more weight than spamming MMOs. Think original wow with having a fireball as your move for the beginning and thats it. This game was much more geared to working together than any MMO i've played and the beginning is really a poor example of how the end game plays out.
I do hope you get to enjoy it a bit! Don't get burned out and honestly, if you hate it and still wanna do the story...grab a youtube video of it. You lose the immersion factor but at least you can watch it in a continuous state. As much as I enjoyed many of the stories, it was annoying that you sometimes had to wait hours/days/weeks to progress.
I used to be indecisive. Now I'm not sure.