If your Navigation Home Page does not have the scratch pad, here is how to make sure it is there:
Go to 'My WikiTree' (dropdown top right)
Scroll down until you find 'Settings'
When you are in 'Settings', scroll down until you find the section 'Navigation Home Page'. This is where you can choose what appears, and one of the choices is 'scratch pad'.
Don't forget to click on 'Save Changes'; the dark green button at the foot of the page!
I keep my useful links in there.