tictactoe

Hi tictactoe,
Welcome to Affinity Forums
Just tick the magnet icon in the main toolbar to turn Snapping on. If you click on the arrow immediately on the right you can set ip up as you see fit. The guides will appear as you move/transform objects. Check this video tutorial for more information:  Snapping and Dynamic Guides 
Additionally you can also check measurements between objects selecting a source object, pressing and holding ⌘ (cmd) and mouse-hovering other objects in the canvas (or the canvas itself) on Mac. On Windows you have to press and hold the CTRL key instead.

It is for publishing long(er) documents. Books, magazines, ad flyers, brochures etc. At present it is very much printing press centred. If you need multipage documents it is going to do a better job than Designer and/or Photo.

It's a joy to have both, tho (and Publisher will rock).
If money is not an issue...As a freelancer, unless you really have a strong source of clients there for business cards, you are going to do a lot of raster and vector work.  If money is an issue, yep, now Designer makes more sense for you. I know a lot of things I can't do with Designer because are more of the field of a raster application, and for those, Photo is great.
For 7 years at latest company, I did most of the design work in Photoshop (flyers, cards, brochures, event posters, etc) . It is doable in certain way, but depends on the jobs/tasks requirements. As a whole solution for freelancing, I see a Photoshop-like (Affinity Photo, Gimp, etc) as a more complete tool in the sense that covers more fields. But those can't certainly export vectors. So, IMO, I wouldn't want to discard any of the two, the raster and the vector tools are a both a must, IMO.