Uninstalling Avast

So not realizing that there was an option in a drop down menu to uninstall avast (the free one), I went and deleted the program file out of applications, emptied the trash, then tried to delete a folder I found in application support. Well, when I try and empty the trash it won’t let me, saying files are in use.

Further googling showed me that I should have done something with unchecking persistence or something? Except I can’t seem to find it since I no longer have the avast program out of the applications folder.

So my question is, how do I get rid of this stuff? Do I have to reinstall avast and then uninstall it?

https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1367

Hi There,
By all means, you have it right! Install Avast again, get the updates…etc… then go to the top left, etc, etc, and get rid of it. I don’t know why however?? Works great and it’s free, don’t even think about Norton!!!
~verne~