Create a daily automation in Automation Studio that includes a single SQL query activity that populates a sendable data extension based on the campaign criteria (joined two weeks ago).

Use Journey Builder Engagement Splits to identify who Clicked the "Download Mobile App’ link.

Use Journey Builder's (JB) Data Extension Entry Source and JB Email Activities

Write a SOL query activity joining the sendable audience with the CLICK data view to identify who clicked the "Download Mobile App" link.

Use Automation Studio's (AS) Query Entry Source and AS Send Email Activities