Yesterday I downloaded Lightroom CC plan with 1TB. I have had previous experience with Lightroom 4. In my new program how do I create a catalogue and do I need to do so? When I click on the drop-down "file" menu, there is no option of "create a catalogue".
Your post moved from Adobe Creative Cloud to Lightroom CC.
You cannot create a new catalog with the new Lightroom CC. This version makes use of only one managed catalog.
You can create new catalogs in Lightroom Classic though.
Apparently you are not aware of the recent change in Lightroom. The Lightroom CC that people have been accustomed to for several years is now known as Lightroom Classic CC. It is the one that is folder based and utilizes catalogs on your PC, functioning similarly to how your Lightroom 4 has functioned. Lightroom CC is a new cloud-based Lightroom that stores all of your master images in the cloud. It is all new, and has limited functionality at this time, but will evolve over time. It is not possible to create different catalogs using the new Lightroom CC.