FFXI is really changed in the last years. The returned can have some problems to take stock of the situation.
Record of Eminence
RoE is a new system to get quests and battlefield ki. To start select and complete [First Step Forward.]https://ffxiclopedia.fandom.com/wiki/Tutorial#First_Step_Forward
Alter Ego
Due to lack of people, SE has created a NPC system that can help you like the old Adventuring Fellow. You can get many alter egos and call up to 5 in party. They have jobs like normal characters. You can call your alter egos with Trust magic. To obtain the Trust magic you have to complete (in any order) these quests.
Trust: Windurst
Trust: Bastok
Trust: San d'Oria
Ilv armor system
Rhapsody of Vana'diel There's a new (free) expansion. RoV will give you a lot of interesting bonus (like exp bonus) and access to new Escha zones. I suggest to complete RoV Missions before start doing other activities in game.
[still on work]