clicking "roll critical" will automatically roll on the critical injury table for you and add the injury to your sheet. it shows the difficulty to heal it with a medicine check, and clicking the "heal" button removes it. when rolling an injury, putting anything in the "critical roll offset" field will add that number to your roll (moving you higher up the table, as some racial abilities/talents do) the roll automatically increases based on the number of injuries you have. if you want to roll yourself and then add it to the sheet, just put your roll in the "critical number" and hit add, and it will just add that one directly to your sheet. also, i believe this only functions with the dice roller script installed