...
First, make sure you are not in zoom mode, because clicks will be taken as zooms! Single click on the symbol: it gets into edit mode where you can move and resize it and edit its graphical properties from the ribbon editor at the top of the view area. Note that the filled shapes allow you to remove the filling and just keep the outline. Also note that all the 'line' objects can have arrow heads.
How can I edit the points on a polyline, curve or front?
...
You can add/remove points to a curve when you are in the point edit mode. Right click on a control point and use the actions in the context menu:
How do I add an arrow?
Just add any of the line objects (including polylines) and go to the property editor to add arrow heads to either or both ends of the line.
Can I rotate the objects?
...