The Start button on an iPad is not a physical button, it is a software-based button located on the screen. If you're having trouble accessing the Start button, try the following steps:
Restart your iPad: Press and hold the Sleep/Wake button until the red slider appears, then slide to turn off your device. After the device turns off, press and hold the Sleep/Wake button again until you see the Apple logo.
Update your iPad: Go to "Settings" > "General" > "Software Update" to check if there is an update available for your device. Updating to the latest version of iOS can sometimes resolve software issues.
Force restart your iPad: For newer iPad models with Face ID, press and release the Volume Up button, press and release the Volume Down button, then press and hold the Sleep/Wake button until you see the Apple logo. For older iPad models with a Home button, press and hold the Home button and Sleep/Wake button until you see the Apple logo.
If none of these steps resolve the issue, you may need to contact Apple support for further assistance.