I'm not very familiar with Hereford EPD's as far as the numbers themselves. Generally speaking higher weaning weight (WW), and yearling weight (YW) are more desirable. Birthweight (BW) is generally desired to lower, the tricky part to get the hang of is that calving ease (CE) or calving ease direct (CED) depending on how different breeds word it is that the higher that number the better.
Like has been said milk (MM) is more or less a preference, some people want a higher milk number and some want more of a breed average number.
You can do an internet search to find breed averages and percentage ranking placements of EPD's as well to see how your bull's EPD's compare
EPD's are meant to be a tool to help in selection.
In my opinion, they are overrated, especially in terms of young animals that have lower accuracy percentages.
To me EPD's are more relevant in a scenario like choosing and comparing proven AI sires that have higher EPD accuracies