After receiving the quest, listen to the Caravan Distress Frequency in your Pip-Boy's radio tab. The message will tell you that the caravan is located east of Wattz Consumer Electronics, past the bridge south of Taffington Boathouse and Covenant. Fast-travel there and defeat the hostile robots. You won't be able to save the human members of the caravan so concentrate on defeating all the hostile robots.
Once done, talk to Ada and get more information from her about the Mechanist and the predicament she's in. After learning your next destination (General Atomics Factory), the quest will be completed shortly and you'll have to bring Ada as your companion. If you have a companion with you at the moment, you have the option to send them to the settlement of your choice.
You'll also have the capability to build a Robot Workbench. This new settlement upgrade allows you to upgrade your robot companions or create new automatrons. You can make as many as you want, provided that you have ample resources to do it. The automatrons you create can act as companions or additional settlement residents.
Before leaving, make sure to loot Jackson's body, his companion, and the defeated robots. You'll obtain Jackson's Holotape and Robot Repair Kits (which are basically stimpaks for your robot companions) and other valuable components that you'll most likely use in the Robot Workbench.