Hi @Edde ,
Granting the Website Contributor built-in role to the user on the resource itself should be sufficient. First you would either create or invite the user into your AD tenant if haven't done so already.
Next add the user at resource level or at the resource group the resource is sitting in, completely your digression.
If you're using Azure AD Premium P1 or P2 license, you can also create a custom role similar to AAD built-in roles specifically for external contractors.