Replace the SSL certificate to linux web server

Application guy gave me two .pem files for two sites.i will need to replace it in proper path in the web server .

Kindly help me step by step process to accomplish that.

my old certs are in the below path :::

/etc/httpd/certs/ServerCertificaatMKCPink.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/onsiteCA-2013.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2014.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/onsiteCA-2012.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/onsiteCA-2011.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2011.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2018.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2012.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2013.crt
/etc/httpd/certs/mijnklantcontact.kpn.com/mijnklantcontact-2015.crt
/etc/httpd/certs/mijnklantcontact-2015.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2012.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2014.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2015.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2018.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2010.crt
/etc/httpd/certs/callmenow.callmenow.nl/callmenow-2013.crt
/etc/pki/tls/certs/ca-bundle.trust.crt
/etc/pki/tls/certs/localhost.crt
/etc/pki/tls/certs/ca-bundle.crt
/etc/pki/ca-trust/extracted/openssl/ca-bundle.trust.crt
/usr/share/pki/ca-trust-source/ca-bundle.neutral-trust.crt
/usr/share/pki/ca-trust-source/ca-bundle.trust.crt
/usr/local/src/perl/libapreq2-2.13/module/t/conf/ssl/ca-bundle-duplicates.crt
/usr/local/src/perl/libapreq2-2.13/module/t/conf/ssl/ca-bundle-sample.crt
/opt/conf/server.crt

i know how to convert file from .pem to .crt .But bit confused where will we actually place the .crt file

Kindly need your help