The default IP address is the browser ip address you are using.
If you want to check the node on the computer you are using or a computer in the same LAN, leave the default value.
If you want to check another computer located on another lan network, enter the ip
The default port to check is 31402 (this port is the default in the pi node software and is used by 99.99% of nodes according to my statistics).
Only change the port if you really understand and want to check.
Checking a node involves sending a SCP connection to your node,start handshake and sending a hello message with Pi network testnet config., and then reading the returned messages.