Problem with converting file

Whenever I download I file and then drag it into Horizon it Says 'NOT VALID CONSTFS PACKAGE’
What can I do I am not able to use any mods. All the mods I download are from nexus
BTW I am new to modding
And most importantly which file formats does Horizon support?.Can someone please recommend a program which converts zip files to files supported by Horizon
I have downloaded my mods from a website which wikihow claims contains xbox supported mods
for example I downloaded the "Overlook Tower Mod '
Can someone also recommend a website which has xbox mods if it is not possible to convert Zip files to Horizon supported files

It sounds like you’re trying to add a PC mod with Horizon which is not possible. If that’s not the case give us some more details.