Bug reporting can be done through this mod's Github issues page.
https://github.com/NeonOcean/S4.Refer/issues
Note: You can get to The Sims 4 folder by going to your documents folder, then to Electronic Arts > The Sims 4 (You must have run the game at least once for the mod folder to appear).
Before reporting a bug you should make sure that everything is installed correctly, if the problem lies with your setup you may just be wasting your time making a report. You should also check to make sure you are on the most recent version of the mod and game, the problem you are encountering may have already been fixed in more recent versions.
The first step to actually reporting a bug is to collect the data necessary to do so. Navigate to your The Sims 4 folder and look for another folder inside named "NeonOcean" and any files prefixed with "lastException" or "lastUIException". If none of these files exist you can move on to the next step, otherwise select them all at once by holding the shift key and clicking each item. With the correct files and folders selected, right click any selected item and do the following.
Windows Computers: Go to the "Send to" option then click "Compressed (zipped) folder".
Mac Computers: Click the "Compress x Items" option.
A zip folder should then appear containing the collected data necessary to send the report.
After you have collected any information, you next need to make the report, you can do so by going to the site listed at the top of this page and clicking the "New issue" button. If you have not made an account with Github before you will need to now unfortunately. You should now attach the data collected in the last step to the report. For the text of the report you could include information such as the following.