How do I put three pictures(1920*1080 each) in one picture(in 3 parts)?

[Blighty]

(10-23-2017, 04:14 AM)IndianAgent47 Wrote: Yup they are but the part to put into the picture is selected free hand, so I was wondering if there was a way to select equal parts of all the three images

Put in guides at the correct places.

Assuming you want a slight angle on the portions:
1980/3 = 640
Put in guides at (640-100) and (640+100)
etc

Switch on (View > Snap to Guides) and (View > Snap to Canvas Edges)

Use the Free Select Tool to make your selections.

Looks like this: