Sometimes a gallery needs a value that isn't a column of its data: a status worked out from another list, a total, a label. AddColumns adds it as a new column, calculated once for each row, and the gallery's controls read it like any other column.
Filter gives you every matching row; LookUp gives you the first one. Use it when you need one record, or one value from it: the job title of a competency, a person's response to a question, the item with a given ID.
When one value decides between several results (a status to a label, a level to a color) Switch says it once: here's the value, here are the matches, here's what each one gives. It's tidier than a chain of If tests that repeat the same value.
A badge is a small colored label for a short piece of information: a status, a count, a category. The modern Badge control follows the app's theme and has a property, Intent, that picks a color for what the badge means.
A SharePoint Choice column looks like text in the list, but Power Apps gets it as a record. To show the choice, or to compare it with some text, use its Value: ThisItem.Level.Value, not ThisItem.Level.
Inside a gallery, each control in the template needs to show its own row's data. ThisItem is the row: ThisItem.Competency shows the Competency of whichever record that copy of the template is displaying.
A gallery shows a list: one row per record, all with the same design. You design the first row, the template, and the gallery repeats it for every record. Here's how to add a vertical gallery, connect it to a SharePoint list and set it up properly.
A Back button should take people to wherever they came from. The Back function does exactly that, without a screen name: Power Apps remembers which screen was shown before, and returns to it.
A button that opens another screen needs one formula: Navigate, with the name of the screen. Put it in the button's OnSelect, and selecting the button changes the screen.
In a horizontal or vertical container, you can't drag a control to a new spot: the container places its controls one after another, in order. To move one, you change that order. Tree view's Reorder menu does it in two clicks.
