This allows you to add a column of marks or other data to the existing grid. It firstly displays a side panel into which you can enter the column headings - the work title and its maximum mark.
You then click on the Add Marks button in the panel. This now enters the headings you just typed, and prepares a new column for the marks. Note that in order to give you plenty of space to add data, only the rightmost columns will be displayed, plus the student names. You haven't lost the others!
It leaves the focus in the first grid cell of the new column, so you can type straight in. It's best to navigate up and down the column by using the cursor up and cursor down keys. You can correct any value at any time during this process. Enter X for absence (or no mark awarded). You can also enter grades (A*, A, A/B, B, B/C, C, C/D, D, D/E, E, E/U or U) but if you do this, make sure that the work item title begins with the letters REP (or rep), e.g. report Nov. 04.
When the column is complete and checked, click on the Accept Marks button in the side panel. This will accommodate the column in the style of the earlier ones, and reset the window ready for a further operation. Remember that you have added marks only to the displayed grid - not to the Markbook90 file. You will need to Save. You can add further columns of marks by selecting menu option Add Marks again, and Save after adding all of them. Or you may prefer to Save after each one - if the computer fails, you will lose data added since the last Save.