How to figure out the discounted price of bond selling at 6% but market is 8%

It involves several steps. Here's a couple of other threads on the topic where I've gone through these steps. You can come back and ask any specific questions about whatever you don't understand:
https://www.askmehelpdesk.com/finance-accounting/computing-bond-price-199941.html
https://www.askmehelpdesk.com/finance/how-do-you-compute-current-price-bonds-200150.html