Step 1: In photoshop, select Lasso Tool button in the tool box.
Step 2: start to select the object by pressing and holding ALT button in your keyboard while using your mouse clicking along the outline of the object. If you release the Alt key, the selected area will be closed. So don't release it until you finish "drawing" the outline. After finish "drawing" the outline of the object, release Alt button. Now, you will have a selection area of that object.
Step3: choose white color as your foreground color in the tool box
Step 4: Edit / fill / . Make sure that the "use foreground color" option (this is the dufult option of filling color.) is checked.
For selecting complex object, you need Pen tool which also can be found in the tool box. But it's not easy to explain here. You can learn it from the Help menu.
Good luck!
Step 2: start to select the object by pressing and holding ALT button in your keyboard while using your mouse clicking along the outline of the object. If you release the Alt key, the selected area will be closed. So don't release it until you finish "drawing" the outline. After finish "drawing" the outline of the object, release Alt button. Now, you will have a selection area of that object.
Step3: choose white color as your foreground color in the tool box
Step 4: Edit / fill / . Make sure that the "use foreground color" option (this is the dufult option of filling color.) is checked.
For selecting complex object, you need Pen tool which also can be found in the tool box. But it's not easy to explain here. You can learn it from the Help menu.
Good luck!