GTM and LC question

Hi experts, I have a question on GTM and LC design. I'm pretty new to these, so please bear with me. I have a production DC with 2 ISP links, which I want to manage them by the LC. Besides that, I also have a GTM with is supposed to fail over to the DR site, where another GTM is sitting there. Other that these devices, there are no other DNS in the network. I'm confused with wide ip setup, especially on the LC, please correct me if I'm wrong, I will configure the wide ip on the GTM, and then add a CNAME record in the GTM to direct the wide ip to a CNAME which I shall use it to configure in the LC to manage the inbound load balancing of the 2 ISP links?