Mutual TLS between client to KONG

Hi ,

Could you please help me how to enable Mutual TLS between client to KONG request .
i have multiple clients (each have their own domain cert ) they need to be authenticated at kong (route based or global based MTLS plugin , where to upload all the client certs in kong cert path . i tried to upload client cert and iam getting error as "its not a CA cert ")
client —> kong → upstream
help me how to upload all (i have 10 clients / 10 client certs ) where to upload how to link these certs in MTLS plugin .

thank you …