Don't play F2P because the game is designed to force you to subscribe, more or less. They got rid of the grind too, so now you can pretty much only play class stories and planetary questlines or flashpoints and be overlevelled by the time you get to the next planet. No need for any of the other side quests.
Agent is the best story, followed by Warrior, Inquisitor, Smuggler, Bounty Hunter, Consular or Knight, and Trooper is by far the worst.
After the class story, play through Illum, Black Hole, then Section X, then Makeb, then CZ-198, then Oricon, Shadow of Revan Prelude, then Shadow of Revan, then Ziost, Knights of the Fallen Empire, for what is roughly the correct order of the story.
Try to learn your class as you level, the game doesn't teach players their classes anymore. Ask for help, join a guild.
And get rid of the mobile games. Those things are awful and should be wiped off the face of the planet.
SWTOR is dying, so I'd play it while you still have the chance.
I'm Eudoxia on Jedi Covenant.