Beginner difficulty
Image Achievement:
Having an image in the canvas so you can manipulate it.
How:
In the OS X menu bar, click “Insert”, then “Image…”. That will bring the Finder window up so you can choose the image you want to upload; or drag the image file (it can be from Finder, Pixelmator, Photoshop, etc) and drop it in the canvas.
I find that right-clicking a file then copying it to you clipboard then pasting it into the canvas does not work. I recommend trying it for yourself.
Rectangle Achievement:
Place a rectangle in the canvas so you can manipulate it, like the evil person you are.
How:
Click the shapes icon to the far left in the Sketch menu bar. On the list, click “Rectangle”. Now click and drag your mouse to create a square in the canvas. If you want a perfect square, you can press the “Shift” key while dragging your mouse.
In the Inspector you can use numbers to adjust the size instead of using the mouse if you want.
Masking Achievement:
Making the image masked by the rectangle.
How:
Align the image over the rectangle. If the rectangle is over the image, click the down arrow in the Sketch menu bar when the rectangle is selected.
Select the image and rectangle.
Click “Edit” in the OS X menu bar then click “Mask with Selected Shape”. This will mask only the objects you have selected.
Bonus Achievement:
Rounding the corners of the mask.
How:
In the Layer List, click the folder’s arrow to show the enclosing layers, then click the “Mask” layer.
In the Inspector, drag the Radius slider so the corners are slightly curved.
Three achievements unlocked, plus a bonus one (if you did it)!
Canvas - Main visual working area in Sketch 2.
Layer List - Left area with the hierarchy of objects.
Inspector - Right area with object preferences.
OS X menu bar - The very top bar which has the Apple logo and the time.
Please tell me of any "Let's Plays" you want me to make... and mistakes I made!