Now, you want to start Calibre and from the Preferences menu head to the Preferences/Adanced/Plug-in option. Once there, click on the "Load plug-in from File" icon. From there, navigate to the tools folder you unzipped earlier. Once there, open the "Calibre Plug-ins" folder and choose the load plug-in from file option. You'll need to pick each plug-in one at a time. Every time you do this, it will then give you a message warning you that the plug-in isn't an official Calibre plug-in and it may prove a security risk. Go ahead and OK it.
So far, so good. Now you'll need to configure the plug-ins. To configure them, go to "File Type plug-ins", choose the plug-in that needs work and select. If you don't need a certain plug-in, say you'll never be decrypting secure Adobe PDFs, you won't have to mess with that plug-in. According to Apprentice Alf:
If you have Amazon Kindle e-books that were downloaded to your eInk Kindle, you must enter your Kindle's serial number into the Kindle serial number customization field of the K4MobiDeDRM plug-in. Remove any spaces from the middle of the serial number. If you need to enter the serial numbers of more than one eInk Kindle, separate the serial numbers with commas (but no spaces).
If you have ePub e-books from Barnes and Noble (e.g. for nook), you must enter your name (not your email address) and full credit card number into the customization field of the Ignoble EPub DeDRM plug-in. The name and credit card number should be the ones set as part of the Credit Card unlock code on your Nook Library page. Separate the name from the number with a comma and do not put any spaces in the card number or around the comma.
If you have Mobipocket e-books, where you either entered a PID on the retailer's web site, or you must read them in Mobipocket Reader, you must enter the PID you entered on the retailer's web site, or the PID of your installation of Mobipocket Reader into the PID customization field of the K4MobiDeDRM plug-in. The PID will be ten numbers and letters, with * or $ as the eighth character. If you have more than one PID, enter them separated by commas (but no spaces).
If you have eReader e-books from Barnes and Noble, or from, say, Fictionwise, you must enter your name and the last 8 digits of your credit card number into the customization field of the eReader PDB 2 PML plug-in. Again, the name and credit card number must be the ones entered at your eBook retailer's website as the DRM key/Unlock code
See what I mean about not wanting to use these tools to go into your own free e-book business?
Finally, click on the Apply button in the upper right, restart the program and you're ready to go.
You won't need to choose a "remove DRM" button or the like. As you import books with DRM into Calibre, the program will automatically strip the DRM out of them. No fuss, no muss.
I've been using Calibre and its anti-DRM plug-ins for several years now. While setting it up initially was time consuming, once done it's made my e-book archiving, converting, and reading experiences much better. I hope it will prove the same for you.
Now read this: How to put your movies on your media server