You can't create a new button, but you can show and hide an existing button.
You need to create a property node. Right click on the control or the terminal and select Create>>Property Node. The selected property is Visible, which is the one you want, but you need to make it writable, so you can control it. To avoid writing to the property constantly, you should create an event structure and wire the button's value into the property node only when its value changes (a "Value Change" event). You should also change the button's mechanical action to Switch Until Released.
If any of these doesn't sound familiar, I suggest you look it up in the LV help and in the user manual.
To learn more, I suggest you try searching this site and google for LabVIEW tutorials.
Here and
here are a couple you can start with. You can also contact your local NI office and join one of their courses.
In addition, I suggest you read
the LabVIEW style guide.
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