Have been given a roll top desk, can't figure out how to unlock the drawers:confused:

If it is like mine, there will be 4 little finger holders, underneath the drawer. Reach under the drawer with your hand/fingers, and put fingers in slots. Then usually it's a simple combination of maybe pulling every other holder. You will be pulling on a spring. Try different combinations till you hit upon the correct one.
You can also look underneath, and actually change the combination to what you want. My drawer also has a little bell that rings, when drawer is pulled out.