Work with fields with random ID's

OpenRPA
2

Select the panel with the username and password ( do not just edit the selector, use the recorder to make sure you get the exact PARENT of the two textboxes, or right click and select the parent in tree to the left in the selector window )
Make sure it can find the panel using highlight, then edit the selector and add the following ( remember to add the leading comma , )

,{
    "ControlType": "Edit",
    "IndexInParent": 0
}

Use IndexInParent to 0 to get the first one, and 1 to get the second item.