I am planning on modifying Vlindrel Hall in Markarth. It's not the best city, but I think the house is the best looking, but having lived in several different custom homes by modders, I have become spoiled with a smelter, workbench, and such in the home. I also want to throw in some fun stuff like a vault, library and a bathroom (everyone seems to miss that one)

I'm very new to the creation kit and what not, so am hoping for some tips as to not f*** up my Skyrim files. Two main questions, when moding the home, do I duplicate the Vlindre Hall cell? or just adjust the existing one. Also, I heard it was best not to delete any existing objects, instead move them to a place where they can't be seen.

Thanks for any help

It depends if you want to use it in a current play through or for fresh games. If you want it for use in a current play through you would be best to make a duplicate and re-link the teleport doors, otherwise if you edit the vanilla cell your savefiles will move things back despite your esp being active. You could ignore all the enabling markers that are used in the vanilla cell that kick in when you buy furniture and set it up how you want it from the get go, delete furniture the works. You could probably even have the copy in the same cell side by side but just link up the doors differently.

If you want it for a fresh game, altering the vanilla cell and content inside would work but you would still need to take into account all the disabled furniture and their enabling markers. You can delete existing objects if you know there isn't anything important linked to them and if you haven't been there before during a game play, that's when deleted things can become a headache for your saves.