First, connect SongSelect to your WE account by clicking on the ⚙ gear icon in the upper right corner, then Settings. Then select Connections from the left-hand menu. Connect to SongSelect using an active CCLI/SongSelect email and password. Please note that only users with Admin-level permissions will be able to establish this connection.
After the connection is made, click Songs from the command toolbar at the top of the Presenter screen to start importing.
Use the Filter box on the left to search for songs. If the song is not already in your library, simply find and import the song from the SongSelect results section. If there are numerous results and you're not sure which song is the right one, click the ▶ play button next to the song title to hear a snippet of the song and/or click on the song itself to view the lyrics. Keep in mind that when you press the play button, it may be the right song sung by a different artist than you recognize – that's where checking the lyrics is helpful.
Once you've found the right song, adjust the Import Options and then click Import. The song is now added to your library. From here, you can either exit this screen, or you can Import Again. This is handy if you want to create and keep various arrangements of the same song in your library. You can also Edit the song you just imported or Add to Cue List if you currently have a cue list open.