You will receive this mission right after completing the mission "Shoeleather".
Jackson needs some time to dig up a lead on Wrench. In the meantime, Aiden can take on work with the local resistance movement and collect useful equipment by completing Resistance Missions.
You simply need to complete any three missions (it doesn't matter if you complete three missions for one person or for different people) from the "Resistance Missions" tab and then Jackson will contact you. Then that mission will automatically end and a new one will appear in your journal.
Available missions include:
