Download the file, go to your documents and type "%appdata%" without quotation marks. Then click .minecraft, and go to saves. Place the file named "My House" (The one you downloaded, in the zip file) in the saves folder. Done!

Simple, once you have an account go to "My Account" (Top right) and then go to project and then go to "Upload new project". Fill in project details and add a few pictures and then click "save" at the top right and your done!
If it is uploading the actual save that is the problem, then:1) Go to "%appdata%" without the quotation marks and go to .minecraft, and then saves.2) Find the file you want to upload, right click on it and then click on "Add to archive", then click ZIP not RAR. Then press OK.
3) When you have done this go the Project details page I mentioned earlier. Then scroll down to MCEdit Schematic and click the blue "Upload File" box, then select the file you made in step 2, the ZIP archive folder, then save when done.

For pictures:
1) Go to images and video, then upload file.
2) To get the pictures, go on minecraft, press the "print screen" key, then go to paint and paste the copied screen picture, crop it to how you like and all that mumbo-jumbo.
3)When you have done this, go to the upload file button and find where you saved the picture(s) and then add a caption and save.
4) When you are happy with this go to the large save file at the top right screen, this will upload the entire world and pictures to where anybody can download them!

Please reply to this so I know you heard it, I hope I didn't type all of this for nothing...