@SilverThunderbird
No, you never want to reuse thermal paste. You'll need to wipe the old paste off completely and carefully (especially on the CPU/Socket). Wipe it off before you remove the CPU, with some alcohol wipes and Q-tips. Of course, clean it off the cooler as well. When applying new paste, apply it to the CPU (after it's already installed in a socket. For the amount, I'd say google or youtube it. There are many different opinions out there. Most applications don't make a lot of difference. Personally, I do a "rice grain" application. Never had any issues.
And for the paste brand, I use Corsair XTM50, but you can also get something cheaper, like Arctic MX-4, I had good result with that one too.