Avidemux is what I would recommend off the bat. Did a quick google to check and it's still good. (Hey things change fast in the software world.)
Avidemux - Downloads
Here's a list of some other good freeware video editors.
The best free video editor 2016 | TechRadar
They go into some detail about what which ones can do and how easy (or not) each is to use.
Best thing is to get them and try them out now. As in, start downloading and installing something right now. Then when you ARE ready to post some videos you won't have to hunt programs and learn how to use them.