Lavarel Socialite azureadb2c - how to extend user to setRaw and map new fields

Question

I'm using Laravel Socialite and have added the azureadB2C service provider (https://github.com/SocialiteProviders/AzureADB2C).

The azureADB2C service provider expects a 'name' claim in the token from the B2C tenant but I am only providing first_name and given_name. I want to modify this by updating setRaw(), which is found in socialiteproviders/azureadb2c/Provider.php.

The documentation gives a brief clue on how to do this:

*If you want to add claim mappings, change User::setRaw() function. The claims mappings must be match with claims in id_token which Azure AD B2C returns.

public function setRaw($user)
{
    $user['name'] = $user['name'] ?: $user['given_name'].' '.$user['family_name'];
    $user['nickname'] = $user['name'] ?: '';
    $user['email'] = $user['emails'][0];

    return parent::setRaw($user);
}*

However, I cannot figure out how to do this and I'm really stumped. I believe I need to extend User::setRaw() but I really need an idiots guide on what to change and where to put the files please. Thanks so much!