Hi @JyotiSharmaV
1. if you have used some controlled audience in your activity and activated this activity then the activity report data will show the data.
However if you dont push the activitylive and check the experience , you cna use Preview QA links to see if you have setup the experience as expected.
2. The custom code action is added if you would like to add some settings in the at.js libraray using targetGlobalSettings function of if you want to pass some dataLayer values as key/value pair as mbox params. It is not mandatory, you can skip if it is not required at the moment.
Hope this helps!