The number of trial memberships includes all memberships that were purchased in the respective month. This includes trial memberships that have already been canceled and won't be active after the trial period.
The blue bar ("new trial members") shows the number of trial memberships purchased that month.
The red bar ("lost thereof") shows the number of new trial memberships purchased that month, which were cancelled, either in that or the following month.
The dark blue bar ("won thereof") shows the number of new trial members acquired that month who became paying members (in that or the following month). Those acquiring a trial membership in February and having been won as a paying member in March will appear in the February column under "won thereof".
The light blue bar ("total") shows the number of trial members at the end of that month or month to date for the current month (including trial members having cancelled).