Step 1: Select Options, Preferences and then Tools and Toolbars from the menu.
Step 2: Click on the Tools menu tab
Step 3: Choose the tool/function you want in the tree view on the left and select it.
Step 4: Click on the Add tool button to place it in the tree view on the right.
Optional step
Step 5: Move the new item to it's desired place by using either the up and down buttons or by using drag & drop..
Click on OK at the button of the dialog and you're done!