Hi Shivam,
What you can do is working with JavaScript nodes. To add some listeners to all of the inputs you have.
In "OnReady" of the screen, you can add the following script:
document.getElementById($parameters.InputId2).addEventListener('keydown', function(event){
// if the keyCode is 8 ( backspace was pressed )
if (event.keyCode === 8 && document.getElementById($parameters.InputId2).value === '') {
document.getElementById($parameters.InputId1).focus();
return false;
}
}, false);
The previous snippet will listen to the second input change. When the backspace pressed inside it, the focus will move to the first input.
And we need to add another JS node when the first input changed (On Change event), so the focus will be moved to the second input after entering one character:

You need to apply the previous logic to all of the 6 inputs you have.
One more thing, you just need to validate if the input is number or not using a regular expression function, to make sure that the input is only numbers (0-9).