GTM and LTM Design across DC

Hi,

 

I don't have much experience on GTM and LTM and wondering if you can help me out that what steps I need to take to design and deploy the following requirements?

 

we have two DC one GTM on each site, so two in total and they both need to be in sync for active/active load balancing between DCs.

 

There is no local DNS server, so GTM should resolve all the DNS queries coming from external users (Internet).

 

Few LTMs on each site that will load balance the traffic between local servers.

 

LTM VS will have the Public IP Addresses, these are the IP that GTM will resolve for DNS query.

 

What I have heard that this is a pretty standard design, can you please tell me where to began to design this or perhaps point me in the right documentation that will help me to build this?

 

Will appreciate your quick response,