I am an almost complete newbie - so please bear with me

I am trying to prepare an oolong tea and have a couple of (probably mundanely simple) questions to all you gurus

- "Huang Jin Gui Superior" oolong tea (judging by the price tag it is certainly in the lower to mid-range of oolongs). It is advertized as a lightly oxidized oolong and instructions on the package state that 2.5g tea should be steeped for 2 minutes in 2dl of water at 100C (2nd time: 3 minutes and 3rd time 4 minutes)
- I am using a 200ml Yixing teapot, newly bought.
I have seen several instructional videos on the net, and I think I am doing everything right: correct temperature (slightly under 100C), I pour the water from a certain hight to introduce oxygen into the brew, I discard the first "rinsing" pour, warm the pot etc. And still I can't get it quite right.
I am also confused about brewing times: In some videos they state that oolong should be steeped for about 20 seconds. I am aware of the fact that this is dependant on the type of oolong - but it seems to be way off the 2-4 minutes stated on the package. What gives?
Any advice you could offer would be greatly appreciated!
- Ivan