A pop-up will appear so you can view your recorded video in your default video player.
You can finish a recording by clicking the red circle that shows up in your taskbar, or pressing your recording hotkey again.
If you want to record the entire screen while an app is open, you'll also need to manually select the entire area. You can also draw a custom area to record a specific part of the screen. You can click any window to record that window, or if you're on your desktop, you can click the background to record the entire screen.
ShareX will ask you to choose a recording area.
Simply accept the prompt and wait for it to install. When you start recording for the first time, you may be prompted to download and install ffmpeg, which is the backend for video recording and encoding.
You can press the hotkey for screen recording ( Shift + Print Screen by default) to start recording at any time.
You can close the ShareX window and it'll be minimized to the notification area in the bottom right corner of the taskbar.
Screen recording shouldn't be affected, so you don't need to worry about this unless you want to. Hotkeys that conflict with system shortcuts will have a red square next to them. If you want to change your hotkey shortcuts, you can click Hotkey settings.
You might get a warning because some of the default hotkeys for the app overlap with system shortcuts.