After installation there will be a shortcut in the All Apps screen.
To put a shortcut in the Metro home screen view this to see how it is done for another app.
In the screen shot below a shortcut icon is in the Metro home screen. Click it.
QuickPic goes through all folders finding photos and other images.
Click the bars at top left to get the QuickPic menu.
Click Included folders.
Since I put all photos in MyPics I choose this folder.
The path root>storage>emulated>0>MyPics determines what is shown. At present all I have are two folders.
Click OK in the above screen and/or click the back arrow at top to return to folder views where a representative pic is displayed.
The free storage offered by CM (the authors of Qpic) is also displayed and cannot be removed it seems.
Click on any photo gallery to see them all as "thumbnails".
Click on any pic to fill the screen with it. I can use the scroll-wheel of my wireless mouse to move back and forth through the album.
Click on the screen to reveal a zoom icon at bottom right. Click on the back arrow at top to move back to the album thumbnails.
Click on the Home icon at screen bottom to exit QuickPic.