Social sharing buttons
To use sharing buttons in Journal you can work with any 3rd party service such as AddToAny or ShareThis.
You can access AddToAny Button Generator here and customize the buttons you need. A code will be generated which you can copy and paste into Journal, in a Blocks module found in Journal > Modules > Blocks.
If you imported any of our demos, you can already see such a module created in Journal > Modules > Blocks > Share Plugin... You can use the same or just paste your personalized sharing code there.
With the Blocks module created, you can add the generated code inside the product page via Journal > Product Extras > Extra Modules, or any other page via the layout builder in Journal > Layouts > ...