The manual and drivers can be downloaded from Xerox.
The Knowledge Base is remarkably helpful. Notable articles include:
There's a whole page talking about free ink for the 360.
The printer supports both PCL 5 for black & white and PostScript 3 for color and black & white but the supplied drivers only support PostSript. While PostScript is a fine language and exploits all the printers features, it is slower to render, especially if the printer only has the 24MB base memory.
PCL is noticeably faster. PCL drivers, like PostScript drivers, are quite generic, and drivers for one printer are likely to work on another. The LaserJet 4000 is of similar vintage and performance, and it's driver can be re-purposed with few changes.
If you let or force the printer to cool below a certian temperature, the printer will run a “cleaning page” to purge air-bubbles and contaminated ink from the head. This is essentially a 100% coverage page and uses as much ink as 20-30 regular documents. Obviously this should be avoided!
Regular use seems to render the pickup rollers unable to grab the paper from the tray, usually resulting in a “Jam:open front cover” error and a sheet of paper half-fed into the machine, or a jam in the paper cassette (media tray). Tektronix has a fancy cleaning tray and automated cleaning routine for this, but your decade old printer is likely missing these bits. (the tray is part 016-1341-00 and directions for it's use start on page 7-34 of the manual). Using alcohol, open the front, and clean the lower black and white rollers. There are better directions on page 7-39 of the manual.
If you're printer continually complains of “replace media tray”, and you've already wiggled and jiggled the paper tray, the paper tray id notches may be broken.
Pull out the cassette and look at the front right-hand side (behind the “letter-sized” or “A4” label, or below the “transparency” label). You should see a series of three notches, most likely all empty. The printer (and virtually all other printers of this vintage) use these to determine when a tray is inserted and what it contains.
Block the top slot for letter sized paper or the middle slot for A4 sized paper (yes, you can convert an A4 to letter or letter to A4 this way). The bottom slot is blocked by a small plastic slide and toggles between paper and transparencies.
If you're running low on ink (less than 1.5 blocks) the printer will helpfully inform you of this. You should probably order more.
If you're running very low on ink (less than 1 block) the printer will report “out of ink” and refuse to do anything. This is particularly annoying since you're not actually right out of ink, and if you're out of C, M, or Y blocks, you're prevented from printing in black & white too!
Thankfully the printer is quite simple, ink level is sensed by how far forward the “pushers” for each color move. Select a suitable object about the same size as an ink-block and drop it in. The printer will happily continue on.
I've cut some appropriate sized blocks from a cardboard tube. If you're going with an open-ended object, cover the ink-end with some tin-foil or wax-paper, otherwise it'll burrow through the warm wax. Small kid's toys (particularly duplo) are good for this.
Do remember to actually order ink though.