Selection related tools

Select one by click
To select object tap on it's bounding box once.

Select multiple by click
Enable Select multiple objects sub-tool, tap to select multiple objects on their bounding boxes.

Select by box selection
To select object(s) tap and drag your finger to the opposite side of the selection area. Only objects falling 100% inside this area will be selected.

Deselect everything by click
To deselect all selected objects tap outside of any object's bounding box once, in free space.

Re-select one from scratch by click
To deselect already selected objects and select a different one, disable Select multiple objects sub-tool and tap on the desired object once.

If object has several effects applied to it which distort its shape it might be easier to select it by name from Layers list or by using a box selection with wider area (be careful not to select what you don't want to).