How to create a library in Rekordbox 3 ? *Urgent

Hello,

In the old rekordbox, when ejecting the usb device,  there is a option to create the library. This usually took a while (5-10min). I can't seem to find this option in Rekordbox 3. I went to preferences -> devices and i chose the CDJ's, just like in the old rekordbox. But when i eject the usb device there is no option to create the library. Am i missing something? It would be a shame if i go play a gig tonight and the rekordbox database isn't solid..

Need help ASAP! Thanks!