The integration between Toolset and Twenty Fifteen theme makes it easy to add custom content to Twenty Fifteen and display it, on the front-end.
For this integration to work, you need to have the following Toolset plugins installed:
Of course, you also need to have Twenty Fifteen theme.
Depending on your site, you may also need CRED and Access.
When you ask for help, please explain what you are trying to achieve, show us what you are doing and explain what you expect to see.