Download/Install a program that you can use to zip a file (WinRar, 7zip, etc)
1. Press the Windows key and R at the same time
2. In the search box, type %appdata%
3. Go into your .minecraft folder
4. Go into the saves folder
5. Right click on the world you want to upload, and select "Add to archive"
6. Select ".zip" in the thing that pops up, and press Okay
7. Go to PMC, create a project, and select the zipped file to upload

SkullFace_tell me how terrible these instructions are.

Copier! >:(

too hard

i mean on windows 8

Windows:

Step 1.) Go to the location of your .minecraft file (normally in %appdata%)
To get to %appdata%, click on the start menu button in the corner, and search for "%appdata%" (no quotaions) or type that in Run in versions older than Windows 7
Step 2.) Open .minecraft
Step 3.) Open the saves file in .minecraft (named "saves", no quotations)
Step 4.) Copy the file of your world to your desktop (should be named whatever you named the world in minecraft)
Step 5.) Create a new post in the projects section of PMC
Step 6.) Upload the world file to the PMC post
Step 7.) Write the description
Step 8.) Post the post
Step 9.) Tell me how terrible these instructions are

Mac / Linux:
I have no idea