Install openssl on a computer and make sure it's included in system variable's path

Create INI file (yourfile.ini) with following details : 
<code>
[ req ]
default_bits=2048
prompt=no
default_md=sha256
distinguished_name=dn
req_extensions=req_ext

[ dn ]
C=LU
ST=Luxembourg
L=Luxembourg
O=YourCompany
CN=yourserver.yourcompany.local

[ req_ext ]
subjectAltName=@alt_names

[ alt_names ]
DNS.1=yourserver.yourcompany.com
DNS.2=www.yourserver.com
</code>
\\
Open a cmd prompt and type the following command:
<cli>openssl req -new -nodes -newkey rsa:2048 -keyout key.key -config yourfile.cnf -out certreq.csr</cli>
This will create 2 files :
\\
key.key \\
certreq.csr
\\ \\
Open the webpage of your CA : https://yourserver.yourcompany.local/certsrv \\
Chose Request a certificate \\
Click on advanced certificate request  \\
Copy the content of the csr file created before in the Saved request box \\
Select the WebServer template and click Submit \\
You will then be able to download the Certificate as CER file and the Certificate chain as P7B\\ \\
If you need to change the CER file to PFX you can do the following:
First transform the CER to PEM
<cli>openssl x509 -inform DER -in certificate.cer -out certificate.pem</cli>
Include then PEM with key to make PFX 
<cli>
openssl pkcs12 -export -out certificate.pfx -inkey private.key -in certificate.pem</cli>