Step 1: Navigate to the bottom toolbar and select the 'Grid Settings' icon. 

Change the major grid spacing to 100mm

Change the minor subdivisions to 10.

You should now see the grid size change.

Step 2: Press the L key on your keyboard to enter the LINE command.

Select the plane that you would like to start sketching on. In this instance we will use the YZ plane (the back wall).

Step 3: With the line tool still selected, left-click to start a new line where the red and green lines overlap.

1. Draw a vertical line that extends 100mm.

2. From the top of the vertical line draw a horizontal line that extends 20mm to the left.

3. From the end of the horizontal line, draw a vertical line that extends 20mm downwards.

Press Escape to exit the line tool.

Press L to start a new line at the bottom of the vertical line.

1. From the bottom of the vertical line draw a horizontal line that extends 20mm to the right.

2. From the end of the horizontal line, draw a vertical line that extends 20mm upwards.

Step 4: With the line tool still selected, 

Step 5: Click on the green tick in the top right corner of the screen to 'finish sketch'.

This will change your view to isometric.

Step 6: Press the O key on your keyboard to enter the OFFSET command.

Select the line that you created in Step 5 and then drag the handle inwards to create a new parallel shape inside. Enter a dimension of 2mm and press Enter to confirm this.

Step 6: Press the E key on your keyboard to enter the EXTRUDE command.

Select the rectangle you created in step 3 and pull this outwards. 

Size should be 2mm exactly.

Congratulations. The bent hook is now complete.