Step 2 : Flying Dolphin* fast boat : Piraeus -> Poros port (Not Methana) (1h - 25€) Every day. Every 2 hours. Until +/- 18h30. Buy your tickets at the port or online : https://www.ferries.gr/en/
*Plan to arrive 30 min before departure - You will have to fill an "anti-covid" form and be able to prove vaccination, Test (Rapid or PCR), or recovery. The boat might stop somewhere else before Poros. Aks where you are before getting out :)
Step 3 : Poros port -> Galatas
Mini ferry - Every 30 minutes - (3 min - 1€ ) or Mini taxi Boat every 10 min.