You will need a metric feeler gauge set, and a way to rotate the engine safely, ie, so it doesn't start accidentally. You can remove the coil wire to be extra safe, and use a large socket on the front crank nut. Starter bump-switches typically aren't accurate enough to stop where you want them to, or at least that's been my experience.

There are better guides online, but in a nutshell, you rotate the engine until the valves are closed (TDC) for a particular cylinder, then you slip the feeler gauge in between the cam and follower pad. You may need to try a size up or down to determine what the gap is, then since you're there, you may as well adjust if needed.

You can do some of the other cylinders' intake and exhaust valves at the same time, or just rotate each cylinder through TDC and do both those valves at once.

BTW, when setting valves: too tight is just as bad as too loose. (This ain't spring break. )

Edit: I just watched the video. How many horsepower does the red valvecover add? LOL. sounds like you have knocking on overrun.

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