If you have not used Pact before, consider trying it out on a spike application first.
Using the technology stacks of your consumer and provider
respectively, write a consumer test for a single endpoint (eg
Generate the pact file.
Send it to the provider team. This doesn't have to be fancy, you can just email the file.
Get the provider team to implement the provider, and verify the pact.
Next, you could try adding provider states and matchers. Make sure you understand how the pact generation and verification steps work.