Here is what the defaults for upstream should look like
View attachment 40859
with the exception that if you already had a lan defined it would appear as the domain you already defined. Also, you wont see the ip6-prefix arpa if you have ipv6 turned off when you install.
here is what the private reverse looks like:
View attachment 40860
obviously if your local network IP address is different that the 192 range it will appear differently (e.g. 172.)
the [::] is used to wildcard reference any local port :553 listening address of dnsmasq.