Making a 4 strand braid isn’t much harder than making a 3 strand one. The extra strand takes a little getting use to so I would recommend practicing a basic 4 strand before moving on to the 4 strand French braid.
[The 2nd and 4th strands get crossed over and then the middle 2 are crossed over each other. These two steps get repeated to make the braid]
[Here’s what it looks like once the steps have been repeated]
This video shows me making the 4 strand French braid. The new strands of hair from the right and left sides get combined with the far right and left strands of the braid. New strands only get added after you have finished the first two steps (see above pic) The trickiest part is keeping the 4 strands separated. I found that holding them in between my fingers was the best way.