What do I do so that only specified components are selectable, and the rest are non-selectable?
Use the "Locked" feature (check the "Locked" box in the component properties) for the components you don't want to be able to select.
Or, if you want most of your components to be locked and only unlock certain ones, you can select all components on the board, open the PCB Inspector, make sure that you only have Components displayed by clicking the text next to the "Include" text at the top of the inspector, and check the "Locked" box. This will lock all of the components. Then you can use the PCB List to unlock specific components.
\$\begingroup\$ Thanks! Is there also a way to make the unselected components greyed out? Such as when you use the search bar at the top right of the screen, and the selected net or component is colored while everything else is greyed out? \$\endgroup\$ Sep 8, 2017 at 18:59
\$\begingroup\$ Yes, right-click an unlocked part and select "Find Similar Objects". Change the setting next to the "Locked" checkbox from "Any" to "Same". This will select all components that are not locked. Before clicking "Apply" or "OK", down at the bottom of the "Find Similar Objects" window change the dropdown from "Normal" to "Mask". This will mask out any objects that don't match your search criteria. Then click "OK". \$\endgroup\$ Sep 8, 2017 at 19:04