There’s a whole list of websites that are trying to compile the working addons for the WoW Classic beta. The easiest one to parse through is Will It Classic. The site has a list of addons — including a search function — and has color-coded each one to signify whether or not it’s working on the beta client. Keep in mind that the client runs on the Legion API, so there are a few semi-current addons that work without any tweaking by their creators.
Dugis Ultimate world of WarCraft Guide installation is not impossible, nor should it deter you from using another guide; remember many are very satisfied with Dugis Guide. However in order to install Dugi’s WoW leveling guide you have to download their installer, you have to download each part of their guide individually (about 16 files). Once you have all the installation setup files and the installer in the same folder, you execute the installers. All the installer does is UnZip each file & place it in your Addons folder. The process is very similar for the Macintosh.
If you're looking for simple, just get actionator. Set it to undercut everything you post for 1c and alt click from your bags. It will place the item on the ah window, do a scan for that item and autoset the price for how much you told to undercut (you can change it accordingly if you feel like it). It will remember if you do stacks for which items and replicate it everytime.