Instead of writing a full code on a single page, you should always divide it into number of smaller codes and place them in separate tabs. This will make your script neat and clean, and will help you to debug easily when you need to test.

For example, if your code needs connecting to one fact table and multiple dimension tables, then you should create a separate tab for each table. Or when you have multiple data sets to be linked in your data model, you can separate code as per the data it links. Just like it is seen in the following screenshot:

You can see from the previous image that different data sets are separated into different tabs to make it more readable. It is very easy in Qlik Sense to add, remove, and rename the tabs.

To add a new tab, you can click on the + sign given at the center of the tab. See the following image:

To rename the tab, you can double click on the name of the tab, just as shown in the following image:

To remove the tabs, you can just click on the cross sign Xshown at the end of the tab name. The following image shows you how: