How do I define the number of bonds formed by an atom?

​To specify this in a ConQuest query, define the substructure in the Sketcher and then right click on the specific atom of interest. In the resulting drop-down menu there is an option to specify "Number of Bonded Atoms" - choose the required number from this list and the restriction will then be shown as an atom label in the sketcher (e.g. T3 for exactly three bonded atoms).

For example, if you've drawn pyridine in the Sketcher and want to ensure that you only hit structures containing pyridine and not pyridinium or metal-bound pyridine, you can specify that the nitrogen has exactly two bonded atoms.