> ## Documentation Index > Fetch the complete documentation index at: https://docs.qxlabs.com/llms.txt > Use this file to discover all available pages before exploring further. # Columns and processors Every column in a grid runs a **processor**. This page covers adding a column, wiring it to other columns, and controlling when it runs. ## Add a column Click **Add Column** at the right end of the header row (**⌘L**), or right-click a header to insert one beside it. Pick a processor from the pane, by category or through the search box, fill in its settings, and click **Add To Grid**. Every processor is cataloged under [Processors](/grids/processors/overview). The processor pane with categories and search, next to a column's settings The processor pane with categories and search, next to a column's settings ## Reference other columns Type `/` in any of a processor's input fields to insert a column. A picker opens listing your columns, each with a preview of its value, and the one you choose drops in as a chip. Columns that hold rich objects let you drill in and pick a single field. The column picker that opens when you type / in a processor field The column picker that opens when you type / in a processor field This is how columns chain. A research column can take your company name and website columns as its input, and when those values change, the research is marked to run again. ## Control when a column runs Open **Run Settings** in the column's settings to run it only when a condition is true. The condition works like a Python expression, for example `${revenue} > 1000`, and you insert columns into it with `/` just like anywhere else. Rows where the condition is false show the **Skipped** status and cost nothing. To try several sources in order and keep the first result, use the **Waterfall** processor, see [Advanced processors](/grids/processors/advanced). ## Credits Each processor shows an amber credits pill in its settings, so you can see the cost per cell before adding it. AI processors are metered by usage, so run a few rows first to gauge the cost. See [Plans and credits](/getting-started/plans-and-credits). ## Manage columns Double-click a header to rename a column, and drag headers to reorder them. Right-click a header for **Edit config**, **Insert column left** or **right**, **Duplicate**, **Sort A → Z** or **Z → A**, and **Delete column**. Use **Freeze columns** in the toolbar to pin the first few while you scroll.