To join the server, go to steam, click on "view" > "servers" > "favourites" > "add server". Then you copy the IP and paste it in the window. Later clicking "add adress to favourites". Done! Now you should find the server on favourites in your ARK server list.
Note: Server is hosted in EU!
Here are some pictures of how it should look, even if it is in swedish I hope you understand what to do :)