setting tpWD9960 to allow pings safely

My aged brain is finding it difficult/impossible to configure the enormously complicated sets for this router.
Any help would be really appreciated..

Makes one think we have invented another process in the W.W.W. that has become our master?

Firstly I presume you’re trying to ping the router from its external (WAN) address, rather than its internal LAN address? If so then the target IP address for ping tests should be the same as what’s returned by visiting say https://whatismyipaddress.com/ and using that address.

If however your ISP is using CGNAT then basically the address returned above would be the CGNAT external / public IP address provided by the ISP and not that of your actual router.

If you log in to the management web portal for the router then you should be able to see the WAN address it’s been assigned by your ISP and if that’s the same address as returned by the test above then you’re router is publicly ping-able and that’s the address you should be using for any ping tests etc.

The next thing you need to check that pings are actually being allowed. See user manual here and visit Advanced -> Security -> Firewall and DoS protection on your router management portal

Ensure in that page the box labelled “Ignore ping packet from WAN port” is unchecked.