How to use custom tag source

Hi i am pretty new to this so sorry in advance if my questions seem stupid. From what I can see the script allows you to match your songs from apple or iTunes right? However, I have no clue how to use it. I downloaded it, and un-zipped it but I have no clue what to do after that to get it to work inside MP3tag. Can someone give me step by step instructions please?
thanks in advance

@Devansh7787

Hi i did that, and sorted a couple of albums out. Once I put these albums into my phone through iTunes, something weird happened. Each song had two copies. One copy was numbered properly, whereas the other copy had no numbering and below the name of the song was "By XYZ". XYZ being the composer instead of the artist. So eventually I have two version of one song, both in a different way of organisation that makes my entire library kinda look bad. On top of that the second version, where it shows the composer, I cannot manually hold it down to delete it. When I click on the second version to play it and then delete it through the player, both the songs get deleted. However this only happens on my phone, on my Laptop iTunes library it's all normal.

to see where the problem is, I made two copies of one song that I have yet to edit. The first version, without editing I put it in iTunes and from there put it in my phone, which to my surprise did not have any problems. Whereas, the second copy of that song, I put the tags and correct information through the iTunes API in mp3tag and then put it on my phone, and the same problem continued.

I know the problem is that there is some data being written or some tag being put into my songs that make one song show twice but I have no clue what that tag is because I'm not expert so I was wondering If you could help me figure out what may be causing the problem and help me solve it. Sorry in advance for this being too long as i wanted to make sure you get the most clear view of my problem as possible. THanks in advance!!
Also I've put a picture below so you know what I'm trying to say.
WhatsApp Image 2021-01-09 at 10.46.23 PM|230x500