Its sounds that simple, but for me, that didn't really work as easy as it sounds.
When you do fill it, it'll fill pretty quickly, then slow right down half way through. I found that I had to be really really patient with it. Fill the neck, then let that slowly sink down. When you're doing so, there will be bubbles and fluid coming out of the bleed screw. I got to the point where the marker guage was waaaaaaaay above the max marker, and fluid was coming out of the bleed hole .... basically too much fluid in the system, and that was following the above instructions.
To counter this, I started the engine, let the fluid flow out of the bleed screw until the marker level drifted back down to normal. Then closed the bleed screw and put the cap back on and let the engine get upto temp. After it cooled back down, I then re-checked the levels , gave it a tiny top up, and since then its been perfect.
Personally, I think its very important that once you've filled it, you don't walk away with it filled above the MAX marker thinking "it'll be fine as there is more in there than I need". If you do need to get fluid back out, then opening the bleed screw is a good way to get the level to drop in a controlled manner .... just make sure thats done when the engine is cold.