???

I don't know if anyone else has responded to this elsewhere, but I figured it out.

You've got a grid of numbers, (say, a bunch of: 55, 1d, BC, etc). A long the right of the hacking console, you have a list of what you can upload and the sequences you'll need to get to install those. Say, a simple one might require 55 and 1d, while a more complex one needs 1d, 1d, and BC. You start at the top and select a value (say, 1d). This opens up the column with that number in it, which you can then select, which opens up a row, which you can then select, and I think that's it.

So if your grid looked like this:
[ 1d, 55, BC ]
[ 4X, 1d, 1d ]
[ 1d, BC, 4x]

And your options were:
Minor hack 55, 1d
Major hack, 1d, 1d, BC

If you wanted the second one, you'd pick them like this
[ |(1d)|, 55, BC ]
[ | 4X |, 1d, 1d ]
[ | 1d |, BC, 4x]

[ (1d), 55, BC ]
[ 4X , 1d, 1d ]
[ -(1d), BC, 4x-]

[ (1d), 55, BC ]
[ 4X , 1d, 1d ]
[ (1d), (BC), 4x]

And you'd have your second hack installed, but not your first. Sometimes it's possible to install multiple, depending on the sequences you're able to work out. So what you should do when hacking is first look everything over, then find the sequence you want and the route to get there, and then quickly click on them in sequence, keeping in mind that what you pick will limit what you can pick next.

hold tab

The minigame? The quick hacks?

If it's the minigame, it works like this. You have a grid of pairs of numbers (I know there are letters too, I'm going to call them numbers because without checking I suspect they are Hex numbers or something) and a number of codes to enter, with the result listed next to them.

Let's say you only have one code, and it's three sections long - say 55 , 1D , F0

To begin with you can only select codes from the top row of the grid. As soon as you choose one the timer will start, so don't jump in, take your time and plot your route before starting.

Once you've chosen your first number, it will flip to only letting you choose numbers from the column of the number you first selected, then it will flip to row and so on. - so let's say our grid has:

55 , 55 , 1D , 55
1D , 23 , 23 , 23
23 , 23 , 23 , 23
1D , F0, F0, F0

Here you can see that if you choose the second or third 55 along, if you look down it's column, there are no 1D's so you won't be able to get the sequence. Therefore you know you need to choose the first 55. Looking down the column you can see that you have two choices of 1D's but if you choose the first one, then it's row is all 23's so again you will fail. You will have to choose the second one in the bottom right hand corner, and then any of the F0's will do.

Once your code is in, don't forget to press Esc to end the timer.

Note, you can have characters before your code that are not part of it - so if the grid was:

23, 23, 23, 23
55, 23, 23, 1D
23, 23, 23, F0
23, 23, 23, 23

then you will have to enter a 23 first before the required code. That will still work.