How do I upload photos from my pc onto my icloud?

Make sure you have checked Photo Stream on the iCloud control panel for Windows, and that your photos are either jpg, png, Tiff or RAW format. Then, to add your photos to photo stream, do the following:

Open Windows explorer, select Photo Stream under Favorites on the left sidebar,:

Click on Photo Stream, then to the right double-click on My Photo Stream. Click on Add Photos on the top the menu bar:

Select the photos you want to import, then click Open.