What is an octopus card ? I am 64 I am considered senior?

It is a smart card that can be used to pay for HK public transportation. As for the specific use and information, you can search at the website;
https://www.travelchinaguide.com/cityguides/hongkong/transportation/octopus-card.htm
As I know, for Octopus Card, people over 65 years old are considered seniors.

If you wanna travel from HK to Jinan, there is direct plane between HK and Jinan, but the flight just operates every Tuesday and Saturday.