overview
If you are using JMP 18 or earlier and want to set multiple value labels at once, follow the steps below.
For JMP 19, please see this FAQ.
procedure
Here we will use the JMP sample data "Analgesics.jmp" as an example to explain how to set value labels for the values A, B, and C in the "Medicine" column as 1, 2, and 3, respectively.
1. Prepare a JMP data table (or Microsoft Excel, etc.) with the following correspondence between values and value labels:

2. Select the area where you entered the correspondence between values and value labels as shown below, and then select Edit > Copy.

3. In the JMP sample data "Analgesics.jmp," right-click the column header for the "Drug" column (on a Mac, hold down the control key and click the column header) and select Column Properties > Value Labels.
4. In the window that appears, click on the field indicated by the red arrow in the "Value Labels" box.

*After performing step 4, a dotted line frame will appear within the field as shown below. On the Mac version, the outside of the field will be highlighted in blue.

5. Press ctrl and V on your keyboard (or command and V on a Mac), and paste the value and value label correspondence table as shown below.

6. Click OK in the upper right corner of the window.