Frame dimensions are a property of the sequence, not the project. A project can contain multiple sequences with different properties.
File>New>Sequence opens a dialog where you can choose a preset or configure custom settings. Several of the preset groups have 1920x1080 options.
Asssuming you have footage of those dimensions that you'll be using in the sequence, then you can simply create a sequence from an asset. Either drag it to the New Item button in the Project panel's lower right corner, or right-click it and select New Sequence from Clip.
Editing mode custom got it thanks.