Add a file to the directory /etc/yum.repos.d/nektar.repo with the following contents
substituting <baseurl> for the appropriate line from the table below.
| Distribution |  <baseurl>                                   | 
| Fedora 25 |  http://www.nektar.info/fedora/25/$basearch  | 
$basearch variable is automatically replaced by Yum with the architecture of your
system.