if you have wordpress installed, and are able to login to the admin interface you can change the information under "settings -> general".
You want to change both "WordPress Address (URL)" and "Site Address (URL)", typically those would be set to the same.
Seeing as you have installed wp under your domain/wp the settings should look like: "
http://www.pluister.com/wp", optionally, if you want wp to load directly from the domain you would need to move all files from /wp to the domain root for your domain (default is a folder by the same name as the domain). If you choose to do so you should set the configuration values to "
http://www.pluister.com".
If you are unable to login, due to domain mismatch for instance, this article could be of some help:
https://codex.wordpress.org/Changing_The_Site_URL
You can use the file manager in cPanel to make changes to files, which for smaller changes may be faster then downloading, altering, and then upload the changed file back.
Once you have made proper changes, you might need to go to "Settings -> permalinks" and resave the option to make sure all links are properly set to the domain you want to use.