System architect at AraxaTech
If you received intermediate certificates and you need to install them you should simply concatenate them in one file in reversed trust delegating order. So if trust is delegated like this:
root -> intermediate1 -> intermediate2 -> your-site
in pem file certificates should be in this order:
P.S.
Installation can be checked with online tools at https://www.digicert.com/help or https://www.sslshopper.com/ssl-checker.html