First point your browser to the Vizier service (1) at http://vizier.u-strasbg.fr/viz-bin/VizieR
Type the keywords you have into the catalog search textbox (2). Here we search for catalogs from the Westerbork telescope. Then click on "Find Catalog" on the right-hand side.
Hopefully your catalog will be found (3). There is a library call-number (here it is VIII/62) for the catalog. Click the check-box to the left of the catalog name to select it.
Click on "Query selected catalogs" (4), and you are presented with a query form.
You can select which table attributes will be returned (5). The form comes with some default choices, and you can change these.
You can query on those attributes. Here (6) we select objects whose major axis is mre than 100 arcsec.
The result is at the bottom of the screeenshot as HTML. If you prefer a different format, more choices are available on the query form.
Vizier can do much more that this simple query. Read about Vizier in the tutorial
