How is radiometric dating used to estimate age

Scientists use radiometric dating to determine the relative age of a new fossil.

Example:

Glossopteris fossils are the most reoccurring fossils in most land masses. In Alfred Wegener’s Continental drift theory which he claims that the continents of the earth may have relocated themselves from their former positions. Which when you synthesize the whole continents you’ll have the "all-earth" or so-called Pangea. The super continent as Wegener’s continental drift theory suggests. These Glossopteris is event in many places mainly in Africa, South America, Australia, India, and Antarctica. That in the paleontological perspective can assert his theory that these organisms have been roaming and surviving all over this one super continent and were dispersed in, that's why they can be found in many places as mentioned.