Hello, in order to be able to move "feauters" that are "Joint", "Cut" or "Intersect" with "Body", you have to create them from sketch, by "Press Pull" (under "Modify" tab), or "Extrude", "Revolve" etc. (under "Create" tab). That creates sketch "feautre" and you can move geometry in sketch, by "Move" command (select an obcject (LMB), then press RMB and menu will appear with "Move" command, select it), or by applying constraints, like "Sketch Dimension" (under "Sketch" tab, just above constraints). "Move" command allow you to use Manipulator to drag object or specify points to move object (from/to).
All that is true if history record is enabled (and that is a default setting, you should see a ribbon at the bottom of your screen), other way to move those feauters that are combine with main body is to stop record history, and in direct moddeling enviromet you can pick previously created feautre, it will be extrude or revolve, and you can use "Move" command , no sketches are needed.
Sound complicated, Fusion have to modes to work with, one that capture history and second without just direct moddeling (please check some learning resources in example : http://help.autodesk.com/view/NINVFUS/ENU/?guid=GUID-856A6ECE-D4D9-4FBA-B8C6-3F1151C973B2). Tools behave differently in each mode, they creates different feauters in feature tree.
Simply, in direct enviroment you can use "Box", "Cylinder" and other tools from Create tab, just watch what feauter will appear in your tree, you can move it easily. If you like to stay in enviroment with history use a sketch to create new geometry (and that only if that geometry will be combine with some already existing geometry. If you select to make separate object, you can use those features from Create tab, and move them afterwards).
Sorry for my bad english.
