I would like just the first column showing in the first transition, the first two in the next and all three in the last. I will have text in the table eventually.
How can you do that?
You could use the same technique as in @Carlatex’s answer https://topanswers.xyz/tex?q=2000#a2242
(if it bothers you that the background and lines are visible from the start, then best remove them. The table will look much better without)