Based on the (limited) info you have given, the utility is saying that 18 (or 0x18?) sectors have already been re-mapped / reallocated (SMART attribute 0x5). Therefore you need to explain more about exactly what you are trying to do, and why you think something more needs to be done.

There is no point spending time trying to explain using MHDD via USB - if you don't understand the instructions already given, then we probably can't make it much simpler, and its functionality is limited when using USB drives anyway.

So, please start at the beginning.

a) You say that you don't need the data from this drive, and so I guess you want to somehow "fix" the drive. What problem(s) (symptom(s)) exactly are you trying to "fix"?

b) Where and when did you buy this drive?

c) If you believe the drive has a problem, why are you trying to fix it, instead of returning it to the place where you bought it?

d) What tests / changes have you done so far with this drive, and what were the results of each test / change?

e) Please supply a screenshot showing all of the SMART data for the drive, including raw values, using whichever utility you can use to gather that info.

f) Which PC OS (Windows / Linux / other) do you use? If it is Windows, then which version(s) do you have access to?

If you supply full, clear and unambiguous answers to these questions, it will help readers to better understand what suggestions are sensible for you.