The project browser can be activated by Tools->Project Browser:
It show all elements of the current program.
To avoid showing also all LiveCode internal program, go to Edit->Preferences->General and uncheck LiveCode UI appear in list of stacks.
Clicking on the eye icon, you set visible or invisible the corresponding object.
Clicking on the lock, you lock the corresponding object. You can't modify a locked object
The blue numbers on the right show the number of code line that the corresponding object contains. This way you can know where code is at.
On the bottom right there are buttons folr creating, duplicate, grouping or deleting objects.
On the bottom left there are button for aligning and distribute objects. Select multiple objects by holding down SHIFT and clicking on the mouse.