Launching the Wolfram Engine is a key task of the Wolfram Workbench.
This can be done in run or debug modes by
launching from a notebook .nb file as demonstrated below.
When The Wolfram Engine is launched through the notebook front end, the default kernel for the notebook .nb file is used. If no special kernel is set for a notebook document, then the default for the notebook front end will be used.
A run mode launches the Wolfram Engine in a normal fashion, allowing execution of code in a fully optimized and efficient manner.
A debug mode launches the Wolfram Engine in a special way that allows inspection of the state of a computation as it runs. The code is not executed in a fully optimized and efficient manner.
Typically you use a debug mode to develop Wolfram Language code. It can then be deployed and executed. This section describes issues for launching the Wolfram Engine in either mode.
Remember that if you want to open a notebook to run your code you do not need to carry out this launch procedure. This is because when a notebook is opened, the Wolfram Engine is configured to set its path to find your code. However, a number of other tasks do need a full launch. These include carrying out a debug session, running a test file, or carrying out a J/Link launch.