# What is a program, and what does the base program do?

A program describes a weekly rhythm made of two building blocks: the base program for the normal case and program entries at their times. It says what runs when. Where it runs, you decide at the display.

> **Type:** concept
> **For:** Anyone who decides what runs on the displays and when.
> **Prerequisite:** Viewing is enough for reading. Creating, editing, and deleting are separate permissions.
> **Where in the portal:** **Programs**

## Two building blocks: base program and program entry

The **Programs** page says it in one sentence: “A program says what runs when. Where it runs is decided on the device.” Behind it are exactly two kinds of building blocks.

| Building block | What it is |
|---|---|
| **Base program** | The content that runs when no program entry applies. Every program has exactly one, and it is never empty |
| **Program entry** | A piece of content with a time window and a repeat. In its windows, it sits on top of the base program |

The **Base program** card in the program editor carries the sentence **Runs whenever nothing else is planned.** A display with a program is therefore never empty: the question “and what runs otherwise?” always has an answer. A new program starts with the base program **Off air**. With **Change**, you choose something else under **What should normally run?** The base program can only be replaced, never removed.

A program entry is the exception to the normal case: the lunch menu from 11:30 to 14:00, the club night on Thursday, a holiday notice set up with **One-off only**. A program holds up to 200 program entries. When the cap is reached, the portal reports **This program already has the maximum number of program entries.** If two entries overlap, a fixed order decides: [Which program entry wins when entries overlap?](/docs/programs/about-priorities). A window whose end lies before its start runs into the following day: 22:00 to 06:00 is one entry, and the dialog says **The window ends on the following day.**

![The program editor with the weekly plan on the left and the sidebar on the right: the Base program card with the sentence “Runs whenever nothing else is planned.” (1), a program entry as a colored block above the pale area of the base program (2), and the Runs on card with the display the program runs on (3)](/docs/programs/bilder/bfa93a43-program-editor-overview.png)

*1 Base program card · 2 Program entry as a colored block · 3 Runs on card*

## Four kinds of content in both places

The same four tabs are available in both places: **Scenes · Playlists · Media · Off air**.

| Content | What happens on the display |
|---|---|
| **Scene** | The designed page runs continuously |
| **Playlist** | The sequence runs as a loop, with the durations of the playlist |
| **Media file** | A single image or video from the library runs as an endless loop |
| **Off air** | The display stays dark |

## Where a program runs

A program says nothing about where it runs. The assignment happens at the display, and a display carries exactly one program. The same program, however, can run on any number of displays: a practice with three waiting rooms assigns the same program to all three and maintains it once. As long as no display carries it, the **Runs on** card says **Not assigned to any device yet — you assign it on the device.**

![Four kinds of content fill the base program and program entries of a program. The program is assigned at several displays, and each display carries exactly one](/docs/programs/bilder/e0557769-program-building-blocks.svg)

## What follows

- Set the base program first. It is on the display almost all the time, and the program card shows its preview.
- Then create the exceptions as program entries: times when something else applies.
- A program takes effect only when you assign it at the display. For two displays with the same content, one program is enough. For different content, you need two.

## Related

- [Create a program and choose the base program](/docs/programs/create-program)
- [Assign a program to a display](/docs/displays/assign-program)
- [How does a display decide what is playing?](/docs/getting-started/about-playback-decisions)