Maybe I'm being completely stupid here but I can't believe what I'm experiencing ....

I've imported my photos into the photos app (absolutely ridiculous that the photos MUST be on the C drive) and I'm trying to put an album of photos together from collection. There's about 1200 photos in this album I want and it's only allowing me to click them individually to add?

I've tried Control+ Left Click

I've tried Shift + Left Click

I've tried dragging over the pictures 

Can someone please tell me I'm just missing something obvious here?! I'm already puzzled as to how Windows 10 was ever released with this many issues and lack of features but if I cannot do something as simple as organising photos, I will be in genuine disbelief.

Please, if you know how, let me know!

Thank you!