What a timeline:

Paul Manafort held secret talks w/ Julian Assange in the Ecuadorian embassy in London in late March 2016.

The month before (2/29/2016), he reached out to Trump via Tom Barrack to pitch himself as campaign chair. He was hired in March. Unpaid.

More
2/29/2016: Manafort pitches himself to Trump via Tom Barrack, writing in a memo “I really need to get to Trump.”

March 2016:
-Manafort meets Barrack at Montage hotel in Beverly Hills; discussed joining Trump campaign
-Manafort secretly meets w/Assange
-Manafort hired (3/28/2016)

Roger Stone was the one who convinced Trump to hire Paul Manafort. The idea of hiring Manafort to work unpaid? That was Roger Stone’s idea.

This took place at some point in March 2016. The same month Manafort met with Julian Assange.

March 2016: Manafort/Assange meet. Also:
3/6: Papadopoulos joins campaign
3/14: Papadopoulos meets Joseph Mifsud
3/21: Trump ID’s Carter Page & Papadopoulos as foreign policy advisers
3/24: Papadopoulos sends email w/ subject line: Meeting w/ Russian Leadership — Including Putin
3/29: Manafort (who is broke & in debt to a bunch of oligarchs) agrees to work unpaid for the Trump campaign
3/31: Trump meets w/ his foreign policy advisers

April 2016:
-1st unreported contacts between Trump campaign & Russian officials
-Early April: Papadopoulos goes to Israel to discuss Russia policy
-4/11: Manafort emails Konstantin Kilimnik: “How do we use to get whole? Has OVD operation seen?” (OVD = Oleg Deripaska)
-Mifsud intros Papadopoulos to Ivan Timofeev (direct Russia connect.)