Minato, Obito and Tobirama were marked with Tobirama's jutsu, that was that panel that showed all those marks.
Naruto and Sasuke were starting their assault.
Minato took the attack. Obito was confused by this.
Tobirama used this confusion to make contact with Obito.
Minato used the fact that Tobirama's mark was on him to teleport Naruto and Sasuke to Obito that Tobirama was in contact with.
Naruto and Sasuke were essentially FTG'd to Obito using Tobirama's marks as contact between Minato and Tobirama.
Make sense?