There are a number of ways to select an object or objects. Once you have selected the objects you want, you can group, lock, align, or move them. When an object is selected, its border becomes visible along with eight resizing handles.
Move the cursor over the object and click it. Or you can use Select Next/Previous from the Edit menu.
Click an object, hold down the Shift key, and click on another object or "lasso" the objects by clicking and holding the mouse button and encircling the objects to be selected.
Choose Select All from the Edit menu.