How to use sertificate on MBED TLS?

I am a microcontroller product designer. I ported MBED TLS to STM 32L471 microcontroller. While I do not understand how can I use the certificate. My customer gave me a certificate in the form of a center2m.com.cer file. The file contains the 3 fields:

-----BEGIN CERTIFICATE-----

MIIGVzCCBT+gAwIBAgIMEnU/

-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----

MIIET

-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----

MIDDX

-----END CERTIFICATE-----

tell me please, how to port my certificate to certs.c file. And I see that file certs.c is not use at all yet.