Hi a warm welcome to the site.
If you search inside the amazon preview of this
level 2 handbook for the word observation, the content page will appear and you can click the link to Unit 11 and then scroll down to page 246.
There is also
this free level 2 observations and assessment preview that looks at checklists and tick charts.
There are many methods of observing children, what do you do in your setting?
This is a
level 3 book which you may find helpful for its explanations, search inside for 'observation methods' and then click on the left hand side for page 368
Best wishes