Hi Manan Patel,
Here is command that you should to input while creating CSR.
also follow this link to import cert..
https://support.symantec.com/en_US/article.TECH221433.html
Command:
keytool -certreq -alias tomcat -keyalg RSA -keystore .keystore -storepass protect -file "XYZ.csr" -ext SAN=dns:(ENTER SUBJECT ALTERNATIV NAME HERE),dns:Enter SAN name here