Second Step: What programs to use?
If you have an older Windows (XP or older) you should use Windows Movie Maker (2.1 or 2.0). For the newer Windows platforms, I prefer to use Sony Vegas Pro (I have the 13.0 Pro bit one) because it has many opportunities. Of course, if you can't get to the Sony Vegas you can always try using Wondershare. It's pretty much the same as the Windows Movie Maker and it is free (free to download on the original website of it, which owns the rights).
For Apple products owners you can always use IMovie, though I don't know it very well.
For smartphones It's a lot harder than on PCs and Mac. There are apps such as VivaVideo and others, but to get the features similar to the Windows Movie Maker, you will have to pay some money. Though I think the best way is using your PC or Mac, because on smartphones the editing is still limiting. At least if you are going to pay some certain amount of money, better pay for something PROFESSIONAL AND LICENSED!