How would I do this

[true ivy]

I was surfing the internet for ideas and stumbled upon this and was seeing if I could recreate it to a degree (Just the background) but I'm not sure how to

[forest mauve]

What portions of the "background" are you asking about? Behind the numbers? Because that region is barely visible.

[true ivy]

sorry for not being clear what i meant was how the colors (the blue and pink) over the images in the background on the left and right side blend/overlap while still having the images features visible if that makes sense

[forest mauve]

So, in other words, you just want to "colorize" some iamges?

[true ivy]

i believe so

[forest mauve]

Use an Adjustment Layer. You can try a Hue/Saturation Adjustment with the "Colorize" option checked. Then choose a color. You can also try a Gradient Map Adjustment and choose the colors you want.