Merge Two Sheets into Master

I have two separate Google Sheets that record sales for our two locations. The column headers are identical, so your task is simply to pull everything together into one always-up-to-date master sheet.

What I need: a master Google Sheet that seamlessly imports every row from both source files, tags each row with its originating location, and lets me sort or filter the combined data just as I do now—by date, product, sales rep, or anything else. A formula approach (IMPORTRANGE + QUERY or ARRAYFORMULA) is fine, but a lightweight Apps Script that accomplishes the same thing without manual refreshes works as well. Whichever route you choose, the solution must stay in sync whenever new sales lines are added to either location’s sheet.

Deliverables
• A working master sheet in my Drive that combines the two sources and auto-updates.
• Clear brief notes inside the file (or a separate doc) explaining how the connection works and how I can add a third location later if needed.

If you’ve built similar Google Sheets integrations before and can turn this around quickly, let’s get started.