Every phone feels just a little different in the hand, and every phone seems to have slightly different button configurations too. Some have the buttons on both sides of the phone, while others put everything on a single side. Xiaomi decided to keep the volume rocker and power buttons all on the right side of the phone within thumb's reach, ensuring you can completely one-hand the Xiaomi Redmi 2 without trouble. Taking a screenshot is a little more challenging though dexterously, as you need to hold down both the volume down and power buttons at the same time. Those more skilled out there might be able to do it with one hand, but it's probably easiest to do with two because of the placement.
After holding down both the volume down and power buttons for a second or two you'll see a visual flash and a sound denoting that the screenshot has been taken. Pull down the notification shade at the top of the window, this is the place where the clock and other notification icons reside, and select the screenshot notification to see the screenshot you just made. This will open it with the gallery app which also lets you edit the photo as well. With the screenshot open click on the screen to bring up the on-screen overlay, which reveals buttons on the bottom including Send, Edit, Delete and More. Edit is what we're looking for here, so go ahead and click that.
The edit overlay has four buttons on the bottom denoting four different categories of tools. The leftmost one is a standard set of editing tools and this is the section we're most concerned here, as adding filters and choosing options in the other sections doesn't really make sense for editing a screenshot. In this leftmost section you'll find crop, rotate, flip, adjust, fisheye and doodle. Cropping to a section of the screen to show someone is likely a feature that'll be often used, as is the doodle feature which lets you draw on the screen using your finger and a color slider. This comes in handy for showing someone a location on a map, pointing out objects in a picture, or just helping someone out by circling an icon to click. Once you're done with editing click the save icon on the top right, which looks sort of like an old-school floppy disc from PC days gone by.