All new Windows 10 comes with a package of existing apps and widgets. One of the best widget is Alarm clock in Windows 10. Here is a short guide on how to Use Alarms in Windows 10.
Step 1: Select the Start Button OR type "a" without quotes on the taskbar OR if you are familiar with Cortana, type“alarms” in the type box OR say“Open alarms and clock” to Cortana
Step 2: Open all Apps in the menu
Step 3: You can see Alarms & Clock in the menu. Choose that option and go to the Alarms tab
Step 4: There is an existing alarm set at 7:00 AM. Select that.
Step 5: Change Alarm name, time, repeats, sound, snooze time accordingly.
Step 6: Select Save Button