I would really recommend against using an endmill in a drill press unless you have a collet, not a drill chuck. I assume you do not have one since you are "completely lost", this is not meant to me an insult if you do, it is just a word of warning based on my assumptions. To explain the warning just a little more, the drill chucks are not meant for x and y axis movement, just vertical.
If you did follow the tutorial with the drilling beforehand, then it would be okay to use an end mill at very low sped and feeds (like 25% recommended) and very very carefully (fyi it will cause excess wear on your chuck). I do not agree with the tutorial on using one without a warning, but with that much material taken out it might be fine, but I still would not use a solid carbide end mill. Solid carbide snaps easily and are therefore not good with chatter and the increased runout of a drill chuck. I also cannot recommend a 4 flute cutter. This would probably be your best bet:
http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=2238958&PMT4NO=0It is a 3/8 shank and cutting diameter, centercutting 2 flute (every 2 flute I have seen is, important if you were choosing 4 flute thought), TiN coated high speed steel. Per the tutorial, even with 1.9 in. of exposed endmill it sill has enough left in the chuck (about 1.25 in), and has over 0.25 in. past cutting so as not to damage the jig.
Use the 0.025 in. cuts as the MAX amount. I normally wouldn't recommended more than 0.01, but this seems more finishing so I am more flexible. Also, do use WD-40 or cutting fluid.
Any questions, just keep asking. Everyone has to start from 0 and ask questions to learn.
