Reading some of the "if you can appreciate it" "if you can understand this", "I would'nt recommend this to start off on Tool, you should try aenima" ..etc etc has prompted me to do so.
There is no ideal place to start with Tool, just start.
This album is heavy, if you don't like heavy rock/metal you probably won't like this. If you have an inclination to listen to this type of music then I cannot recommend this album highly enough. The music is amazing, nothing technically difficult in the guitar/ bass playing lots of polyrhytmic drumming, which is excellent. The album is a rollercoaster ride, musically and lyrically. Soft sudddenly becoming heavy. Maynard is a great singer and his lyrics are mind blowing, if a little cryptic. Perfect if you like philosophy. The lyrics are not in the liner (go to the band website for these)...which is all Alex Grey paintings, again if you like spirituality and philosophy.
Musically and Lyrically this album is one which will encourage you to think. Should you choose to do so. You could just as easily "headbang" to it. As for coming to a conclusion on what it all means....well thats entirely up to you. The Individual.
This album is stunning...try it (Listen to it a few times and you won't be able to stop). Then go see them live. I doubt you'll be let down.