This is a partial answer, which explains what the summary means, but unfortunately not when her nomination will actually be voted on.
The Senate Executive Calendar is issued every day and can be found on the Senate Website:
The Executive Calendar is published by the Executive Clerk’s office in the Office of the Secretary of the Senate. The calendar is published each day the Senate is in session. These calendars list executive business items such as unanimous consent agreements, resolutions, treaties, and nominations
The CRS report The Senate's Executive Calendar has additional information:
Treaties and nominations constitute the executive business of the Senate and are the subjects of the Senate’s Executive Calendar. When a Senate committee reports a treaty or nomination, it is said to be placed “on the calendar” and is available for floor consideration
The Senate’s other calendar, the Calendar of Business, identifies the bills, resolutions, and other items of legislative business eligible for consideration (see CRS Report 98-429, The Senate’s Calendar of Business)
From the look of it, the Executive Calendar is less of a calendar, and more of a record/to-do list. In Issue No, 38, released on March 5th, the "Nominations" section begins on page 3. Here you'll see each open nomination, listed and numbered in the order they were "reported" from a committee. You can see Deb Haaland's nomination appear at the end of the list with Calendar No. 31.
"Calendar Number" refers to the number identifying the order of the nomination on the calendar, not to a specific calendar with the date of the nomination on it, as one might expect. I don't think you can find out when the nomination will be voted on from this – it just means the nomination is on the docket and ready to be taken up by the Senate.
From the "About the Executive Calendar" section:
This section identifies presidential nominations submitted to the Senate for confirmation, placed on the Executive Calendar with a sequentially assigned calendar number and ready for Senate floor consideration.
More detail from the CRS report The Senate's Executive Calendar:
Fourth, the calendar lists nominations that have been reported from committee. Except by unanimous consent, the Senate may not begin floor consideration of a nomination until it has been on the calendar for at least one day. Any nominations appearing in this section of the calendar for the first time are listed under the heading of “new reports.” For each nomination, this section of the calendar identifies
- the calendar number that is assigned to each nomination representing the order in which it was placed on the calendar;
- the number of the presidential message by which the nomination was transmitted to the Senate;
- the name of the nominee, the office to which he or she has been nominated, and the name of the predecessor in that office;
- information on how the nomination was reported, such as when and by whom it was reported, which committee reported it, whether the committee reported it favorably, unfavorably, or without recommendation, and the number of the printed committee report, if any.
Nothing much happens on March 6th, but if you look at Issue No. 40, released on March 9th, you'll see on the second page an Unanimous Consent Agreement to proceed with the nominations of Fudge (Cal. No. 12), Garland (Cal. No. 27), and Regan (Cal. No. 15). You can see that the nominations don't have to be processed in order, as Walsh (No. 17) and Guzman (No. 26) were skipped over in favor of considering Merrick Garland (No. 27) for Attorney General, so the fact that Deb Haaland remains at No. 31 doesn't tell you much as to when her nomination will be voted on.