Screen Arrangement

Your monitor’s screen resolution will impact the available settings and external screen capabilities. 

While undocumented, testing has demonstrated that 4:3 monitors with a display resolution of 1280x1024 and below are currently only usable with iPad screen mirroring; as such, associated settings to disable screen mirroring in favour of Stage Manager are not available in iPad Display settings.

When used with a 16:9 widescreen monitor, with a native display resolution of 1920x1080 or greater, the full set of Display settings - and access to Stage Manager - become available.

NB: Only these models of iPad currently support Stage Manager:

• iPad Air (5th generation)
• iPad Pro 11-inch (all generations)
• iPad Pro 12.9-inch (3rd generation and later)

The iPad User Guide lists the upper resolution limit as 6K - but the Guide offers no lower limit, or suggestion of aspect-ratio, being a factor for compatibility:

Connect iPad to a display with a cable - Apple Support

This discussion thread may be of additional interest:

iPad Extended Desktop not working - Apple Community

In conclusion, your monitor must be capable of 16:9 widescreen 1920x1080 (FHD) to support iPadOS16 Stage Manager extended desktop. Unless the monitor meets the minimum required specifications, you will not see the full range of controls in iPad settings.  

When mirroring your iPad display to an external monitor, expect to see black bars to infill where the iPad screen doesn’t match the aspect ratio of monitor screen.

I’m not sure that I understand your question, but if you are talking about the option to rearrange your home screens, tap and hold down on the Home Screen until all the apps wiggle, then tap on the row of dots above the dock. All of your home screens will appear on the screen and you can move them around by dragging them with your finger. When you are done, tap Done in the upper right corner.