Probably a stupid question, but I can't find the solution

My screen used to be like this:



I did always use this type of screen, I can use it with extreme speed.

Somehow it changed to this:



It's really confusing to use this now.

I don't really care what people prefer or think is better, I automatically move to the directions of the first one, so that works best for me. Please tell me how to change it back

Thanks in advance...