PowerShell's Read-Host command can help you collect information from a user input. This simple script:
$CaseIndex = Read-Host -Prompt 'What is the case index number?'
. . . will collect the information for the value $CaseIndex. Press the play button on the upper toolbar to run the script. The question listed after '-Prompt' will be presented to the user, and the answer will be saved as $CaseIndex. When $CaseIndex is entered in PowerShell again, the user entered value will be given.