morgan freeman's questions

I am trying to configure my computer to run its own DNS server. The only thing I want to do is to forward all requests for my.example.com to my-staging.example.com. So, when I would use a phone, who's DNS is my computer, the requests would also be redirected.

I can't seem to figure out what exactly should the zone file contain, could anyone please help ?

I tried:

example.com. 7200   IN SOA ns1.example.com. ( 
                         2008010402 
                         15 
                         3600 
                         3000000 
                         86400 )
                    IN NS example.com
my.example.com.     IN A   213.144.138.203

but does not seem to work.

Any help is greatly appreciated.

Thanks.