Laravel 8 & Media Library: Associating files - laravel

Question

I am using Media Library v9. I am trying to follow this documentation to associate files. However, the package is newly installed to the project and there're lots of images uploaded. Is it possible to add the uploaded media to collection? Like the docs:
$yourModel = YourModel::find(1); // Maybe I can use `id` here instead of a number
$yourModel
->addMedia($pathToFile)
->toMediaCollection();
For my case I have two directories: public/app/lostFound/lostItems and public/app/lostFound/handoverStatements
This was my old code for the image upload:
if( $request->hasFile('LFImage') ) {
$destination = public_path('app/lostFound/lostItems' . $lostFound->LFImage);
if( File::exists($destination) )
{
File::delete($destination);
}
$file = $request->file('LFImage');
$extension = $file->getClientOriginalExtension();
$filename = $lostFound->LFNumber . '-' . $lostFound->lostItem . '.' . $extension;
$file->move('app/lostFound/lostItems', $filename);
$lostFound->LFImage = $filename;
}
if( $request->hasFile('handoverStatement') ) {
$destination = public_path('app/lostFound/handoverStatements' . $lostFound->handoverStatement);
if( File::exists($destination) )
{
File::delete($destination);
}
$file = $request->file('handoverStatement');
$extension = $file->getClientOriginalExtension();
$filename = $lostFound->lostItem . '-' . $lostFound->LFNumber . '.' . $extension;
$file->move('app/lostFound/handoverStatements', $filename);
$lostFound->handoverStatement = $filename;
}
How can I associate the already uploaded LFImage and handoverStatement to the media collection?
This is what I did so far, but it's not directing to the files, but the folder containing the files, which will obviously gives me an error:
$lostFound = LostFound::find('id');
$lostFound
->addMedia( public_path('app/lostFound/handoverStatement') )
->toMediaCollection();