That sounds about right. A few more thoughts:
Ashevillain is right -- putting all the tracks into the tagging box isn't enough. If you want to write tags to multiple tracks at once, you need to first select all those tracks. Instead of the command-A select all tracks, you could also click on the first track in the list to select/highlight it, then hold the shift key down and click on the last track -- this will also select all tracks for tagging.
Tags for date I think were made for things like studio CDs, so devices may/will not play nice if you try to put in month/day/year into the date field. Just use the year for the date field, and then tag the album field with the full date -- 2012.02.05 - Fillmore Auditorium, Denver -- or something like that.
After putting in all the common data -- artist, album, year, etc -- you do not need to "Write Tags" to save it. You can go right to using Auto-name to name the individual tracks and just "Write Tags" once at the end.
For the auto-name, that feature set has been expanded and made more robust over the various generations of xACT. I think you are working with an old xACT version due to your PowerPC mac, so I don't think the "Load track names from File" feature is available to you.
You will need to copy and paste the track names as Ashevillain explained. A few things to note: my experience was that some of the earlier versions (could be the one you're using) did not play well with cutting and pasting directly from some text files or programs. At least, I didn't used to be able to directly cut and paste from the TextEdit app (probably the handling of carriage returns), so I needed to copy from the TextEdit text file into a Word .doc file, and then copy from the Word file into the Auto Name box of xACT. I don't know if you'll have this problem, but if a direct copy from your text file isn't working, try something like this.
Also, again earlier versions of xACT didn't strip away track numbers, so if your text file was:
01 Song Title 1
02 Song Title 2, etc
You will need to first strip of the leading 01, 02, or 01), 02) or whatever, and just feed a list of track names into the auto-name box.