Old Flash Developer looking for a Movie Clip like instance

There are several ways you can combine multiple objects in C3. The easiest is to create a hierarchy. They won't become a single object, but it will be easier to deal with them as a group - you can create/destroy all objects in the hierarchy with a single action, move/rotate/resize/fade them all at once etc.

Also check out the templates feature:

construct.net/en/make-games/manuals/construct-3/project-primitives/objects/templates

Once you set a hierarchy up, you can rightclick the parent and choose "hierarchy > select all children", and then right click once more and choose "wrap selection", to get good movement around the layout view - all hierarchy parts will move together and resize proportionally too.

EDIT: Hmm, I checked keyboard shortcuts, I can see ENTER to wrap selection quickly, but don't see a "select all children of hierarchy" shortcut, unless W works (although it says this is for containers). If W works, then that's super convenient!

There is this property available for the parent of a hierarchy, with the mode set to wrap or all it will now select the whole hierarchy every time you select any of its members. If you want to select them individually again, for example to turn off wrap mode you can hold alt and then click the instance