If you want to save a current query, click on the 
button. A window as shown below will open where you can specify the title and
description of you query.
After you entered title and description of the query, click OK to specify the query group. A window as shown below will open.
Choose a group from the tree or create a new one an click OK. The new query will be included in the selected group.
Finally you can edit the titles and descriptions of
the groups and queries. Click the
button to store the changes. To delete items
from the tree, select it and click on the
button. Click OK to save the new query and close the window.
If you want to load a query that has been stored
previously, click on the 
button. A
window as shown below will open.
Choose a query from the tree and click OK to close the form and filter the datasets according to the selected query.