Need help with a 1 gallon potato vodka mash?

[sttifyd35]

Hi everyone. I understand that you have to cook down the potatoes, mash them up, and strain off the solids. My question is on the sugar end. Im not very familiar with the malted barley end of it besides the homebrew beer kits ive made. If someone could give me a step by step process to it that would be awesome. Also, how much of a difference would it be if i cooked, mashed, and strained the liquid and added a couple pounds of sugar to it? Would it be the same effect and similar flavor profile? Any advice would be great and appreciated. Thank you!