Reddit reviews Monoprice 107043 Punch-Down Impact Tool for 66 and 110/88 Type

All those blue cables and the single white one might be cat5, so the statement doesn't make much sense. cat5 just means it's a 4-pair cable that has a certain number of twists per inch to meet frequency requirements.

If he had said "Row 7 on the 66 block is hot", that would mean something.

Now that I think of it, he could mean that of all the connected rows shown there, only 1 is passing the centurylink signal to a wall jack.

Either way, you need to map what row on that 66 block goes to what wall jack. The usual way is to map it with a tone generator. Trial and error is the other way (e.g., keep moving the centurylink signal on the 66 block until it lands on the wall jack you want).

At the very least, you could get a friend on a cell phone to sit at the wall jack that works while you sit at the 66 block. Start disconnecting stuff one-by-one until your friend tells you the signal went out. You'll have at least found where that wall jack is on the 66 block - or you found where the centurylink signal is coming in. The logic being you either disconnected the incoming signal to the block, or you disconnected the wall jack from the block. A punchdown tool is handy for making connections to the 66 block - just make sure you have the cutting blade pointed the right way.

Thanks for the advice! Do keystones need to be rated exactly for Cat6a, or are they interchangable? I saw this 25-pack on Amazon for 29USD but they say they're for Cat6.

This is the punchdown tool I've got so I think I'm set there. I have ordinary wire strippers (very similar to these), would those work or would I have to buy something like this instead?