An important aspect in the use of Form-UIs is the access to parameters and their stored values.
Determine the parameter with a specific name:
The method parameter('Place') returns as the result the parameter with the name Place, resp. null if the parameter does not exist
Determine the parameter value:
To access the parameter value, two equivalent notations are allowed, for example parameter('Place').value determines the stored value of the parameter Place as well as $Place. If the name of the parameter contains a character that the formula interprets as a delimiter, the notation parameter('<name>') should be used (also see Dollar sign $).
Changing the value of the parameter:
If it has to be possible for the value of a parameter to be not only displayed, but also changed, only the notation parameter('<name>').value is permitted.