Activate application

1. Explicitly: the code runs when the user indicates that they want it to run. This can be accomplished with the 'play journal' command, the 'execute NXOpen' command, a custom button that is configured to run your code, etc. The vast majority of the code on this site is intended to be run with this option.

2. Automatically at startup: the code will be run as soon as NX starts. This can be useful if you have written something like a custom add-in that needs to do initialization when NX starts and it needs to be available to the user throughout the entire NX session.

3. User exit: you can create 'callbacks' that will run your code when certain events happen in NX (the user saves a part, the user adds a part to the assembly, etc). If you have written your own VB application or have written VBA code for MS office applications, this would be similar to writing code to respond to an event. Using this option will add some required code to your project, but there is more to be done to get the link between NX and your code working.