Welcome to the community, @Winky! It seems like you are trying to capture two different question types here. One is the select_multiple question type to capture only three choices (maximum), and the other is an integer question type to capture the percentage.
If this is the case, please be informed that you can only have a select_multiple question type or an integer question type.
This post discussed previously should help you restrict the number of choices for a select_multiple question type:
This post discussed previously should help you restrict the % to 100% for an integer question type:
