By default when you load markets into Guardian they are ordered by Ascending Start time, however you can set your own order simply by clicking any of the column headers (once for Ascending order, twice for descending order)
You'll see a faint arrow in that column header indicating which is sorting and in which direction
So if you wanted them by start time with those starting latest at the top you'd click on the 'Start time' column header again to order by Descending.
If you want to order the by market name 'Descending' you'd simply click the 'Markets' column header twice.
Sometimes you may want to do what's called a secondary sort, this is where'd you'd sort one column first (known as the primary sort) then sort another (known as the secondary sort)
Primary and Secondary Sorting
To do this after sorting your first column (the primary) simply hold down your 'shift' key while clicking on another column header to perform a secondary sort (click it once for an ascending order or twice if you want a descending order)
For example this can be useful in football matches where there are multiple markets for each fixture, you fist order them by 'Start time' in ascending order (earliest first)
But you now want to order them by volume in descending order (either to remove those with low amounts from Guardian or just so you can see those with the most volume at the top), so you click the volume column header twice.
As you can see that now takes precedence over the start time order and some of the later 8pm KO matches are mixing in with the earlier matches
But if you do a primary and secondary sort you could first sort them by start time, then by holding down your 'shift' key while clicking the volume column header twice they would look like this
Notice how this time all the earlier KO are still at the top but then they are sorted by volume, next are the matches kicking off at 8pm order by volume, and if you look closely at the column headers you'll see the faint arrow icons each showing which have been sorted and if they are ascending or decending.
