Using LAN Speed Test couldn't be simpler. Load the program, click Start Test, and it will ask where you want to store a temporary file it uses to test network speed. Don't worry about clogging your PC, it deletes the file after it performs the test.
Once you've done that, click again, and after a few seconds, it shows results for both writing to your disk (essentially the equivalent of download speed), and reading from your disk (essentially the equivalent of upload speed). That's all it takes. Once you've got the results, you can print them.
Don't run LAN Speed Test test a single time and expect to get highly accurate results. From one moment to the next, there may be network traffic condition, and changing circumstances. I found that on several occasions there would be "outlier" results, results that were very different from the vast majority of other results. Run the test multiple times for a realistic picture of your connection speed.
It's also a good idea to run the tests at different times of the day, again to get the truest picture of network speed. If you're a network administrator, that will help you see when network congestion is highest. You may also want to run the tests on different PCs, to see whether certain computers or parts of your network have network issues.
LAN Speed Test would be more useful if it could save results to disk, or even average the results for you. But given that this program is free for business use as well as for personal use, that's a minor quibble. Whether you're a network administrator, or just an ordinary user who would like to know your true network speed, you'll find this a useful tool.