What’a a display filter that matches DNS queries for a particular host name?

The filter for that is dns.qry.name == "www.petenetlive.com".

If you take any DNS query packet you happen to find (use just dns as a display filter first), and click through the packet dissection down to the "Name" item inside the "Query", you can right-click the line with the name and choose the Apply as Filter -> Selected option. Then, you would change the name in the display filter field from the original one to "www.petenetlive.com" which you really want.

Why is it hard - because the generic question is "how do I filter for field X of protocol Y" and there are hundreds of protocols with hundreds of fields each. So there is no chance to have a tutorial for each, so finding a packet of the protocol you want and localizing the field of interest inside it is the most efficient way.