ekim cheel

I'm progressing slowly through the workbook and have got as far as the 'mother of millions' project, 'removing Halos' on page 255. Now I'm not familiar with this sort of stuff, I don't know what a halo is or what it should look like, and even with my best specs on, can't see any difference between the images on p255 and 256, which i presume are meant to be before and after pictures. Can anybody give me some pointers at to what I'm meant to be seeing here, please ?

Firstly, I'm a newbie so be gentle with me, especially if this post isn't where it's meant to be.. I have searched the forums and done some googling, but to no avail I am slowly, as a newcomer to Affinity and to image manipulation or post-processing or whatever you want to call it, working my way through the workbook and the end of chapter two is in sight :-), I'm working through the section on 'Manipulating a live filter layer mask' and I'm confused - steps 6,7,8 are the same as those for the previous section, even down to referring to 'building, road, and traffic lights' that don't exist in the example image for this section My problem is I learn things slowly, step by step, but I'm now not sure what the expceted outcome is here so I don't know if I'm doing it right - could anybody enlighten me please ?