If you play 4-Card Majors systemically, then check the box to the right of the caption.
If you do not routinely open 4-card majors, but will do so as an exception if there is no other good bid or rebid (e.g.: with 2-KQJT-J7654-AKx), then check Excep.
If you would never open a 4-card major, check Never
If you routinely play 5-card majors part of the time and 4-card majors at other times, then check the appropriate boxes. For example, some people will routinely. open a 4-card Spade suit, but not a 4-card Heart suit or will open one in 3rd chair, but no other position, etc.
If you do play 5-Card Majors, then you are sometimes faced with opening a 3-card minor suit. Select which option you prefer from the pull-down list.
Another option is to never open a short Diamond suit, so with 4=4=3=2 shape, you open 1C. The benefit is that a 1D opening always promises at least a 4-card suit.
The notrump choices should be self-explanatory.
For more information about Weak-2 opening, click here.