Freeware to download and install on your machine with risk free no ads and spyware or hidden ware I have already tested and result was good.
With the minimal limitation on Free only put a watermark on your result and can remove by upgrade to pro version only 15$ per year.
Max 15 minutes record On free version,but it long enough to produce some useful tips or guide on how to tutorial for students or teacher.
Link download Screencast-O-Matic
Size 17 MB.
First opening choose Use FREE recorder
Simple UI User Interface even newbie or beginner user can start using this free tool instantly.
How to config
Max time 15 Minutes
Size click to select more options inc. full screen
Narration : Need mic and quiet room.
Audio for Pro version ,so skip on free version
When ready click Rec to start
Builtin player to play back output file inside program or click done in order to save or sharing output file to YouTube account
in brief, this was a good and straightforward simple tools or utilities for home user or mature who want to present some tip or how to presentation and send them to public on social media like YouTube. For up grade to pro version 15$ is very cheap and reasonable to consider.