Making a responsive nav bar

Hi, guys! I’m trying to implement a responsive nav bar similar to this: My code is currently here and I used “float: right” to put my nav bar on the right side of the header. While searching for how to make it responsive, I noticed a lot of tutorials use “display: flex” to set it responsive, but everytime I put “display: flex” on my code, my list goes to the left side and I can’t seem to get it to the right side

. My question is: is there a way to make the nav bar responsive without using display: flex? And how do I put my list on the right side of the header after using “display: flex”? Thank you for your time in advance!

have a look at this:

and those quite a few good ones on youtube, if this is no good, let us know, i’m sure others can provide alternatives

but flexbox/grid is the way to go, float is so 2000’s, your better off learning the new techniques