Is there someone who can give me a simplified, straightforward, and step by step explanation of what to do in order to allow me to be able to run two different versions of Firefox on the same machine, so that I can go back to feeling like when I browse, that I at least understand what I'm doing? This way I can keep abreast of new updates on version 53 up while still being able to use a version of the browser I am more comfortable with using. Please be aware I do not understand technical jargon, and would like the most simple instructions possible.

I have a windows 10 Laptop, and recently updated to version 53 from an older version of the browser. However I am not particularly thrilled with the changes in the new edition, particularly as the upgrade caused an icon for one of my extensions to vanish and the only known apparent fix for it, did not work I am also confused a bit by version 53 due to the fact that some of these changes are a bit odd and seemingly done for the sake of being there, such as the 'recently bookmarked' section of the bookmarks, which keeps throwing me off as I keep thinking at first glance that they are unsorted bookmarks. I keep all my bookmarks in folders, and so this keeps causing an intellectual disconnect for me. I do not wish to downgrade if I don't have to, though if I do have to, I obviously will. What I WOULD like to do instead though, is be able to have the ability to have two versions of Firefox available for use; version 53 for newer sites that cannot support the older versions, and an older version (more than likely version 28.0 which was the last version I was fully comfortable with) so that I can do the rest of my browsing in a manner I am more comfortable with. I have asked about this before, but the answers that I was given links to are confusing on a level I cannot fully put into words as I am not a technologically savvy individual. Trying to figure those instructions out made me throw my hands up in surrender as I had no idea how I was supposed to do anything listed in the links. Is there someone who can give me a simplified, straightforward, and step by step explanation of what to do in order to allow me to be able to run two different versions of Firefox on the same machine, so that I can go back to feeling like when I browse, that I at least understand what I'm doing? This way I can keep abreast of new updates on version 53 up while still being able to use a version of the browser I am more comfortable with using. Please be aware I do not understand technical jargon, and would like the most simple instructions possible.