trouble with plugin mods

I’m attempting to modify 2 separate plugins on my wordpress, at dsrstudio.com, mobile.nav and page tiles.

I am having issues modifying .css and .php files and the changes not showing up live.

With mobile.nav, I changed the primary .css file, while the plugin was activated. I was later informed via these forums that wasn’t a good idea. I therefore uninstalled (deleted) the plugin, and re-installed it. However I notice that the settings come back for my previous install, like the plugin was never deleted. Therefore, my .css changes don’t seem to hold any water either. I have tried making silly changes that would be obvious and they simply don’t show up.

I found code that should change the ordering from descending to ascending for post tiles, here.

https://www.ads-software.com/support/topic/plugin-post-tiles-rearrange-the-tiles?replies=3

This code change has no effect. I tried disabling the plugin, making the change, and re-enabling it. I also attempted to make some changes in a .css file for a mobile nav plugin. Neither of these changes seems to be affecting the website. I have no idea why. I did find something about needing to disable the plugin before making any mods to the related files. So, I tried taking the poster’s advice, and deleting the mobile nav plugin, and reinstalling it with my mods. What’s weird, is despite a clean install, it won’t overwrite my previous settings with it’s default settings. SO, something is cacheing and I can’t figure it out. Please assist. ??