It's a bit hard to describe fully in writing...and once you start into it you'll probably see what needs to be done.
To take off stock:
- there usually 2, might be 3, screws that hold the stock onto the body. They screw through the stock tang.
- take the screws out and slide the stock straight off...you might need to help guide the wiring so it clears.
- there might be (can't remember) a small connector close the the body/mechbox that joins an extension wire that goes into the stock....is so unclip it and put the whole stock aside (don't lose any screws....tape them to the inside of the stock...or whatever).
- the wiring that comes out the back of the body needs to be pulled back into the body and "turned" upwards at the back left side of the mechbox....you won't be able to do that without taking the mechbox apart.
(in general...mechbox.com might have an AK disassembly guide...the Kraken is the same as the TM AK).
- take off selector...pop the little cap, undo screw, lift selector arm out...there's a bushing and a "socket" that has to come out too.
- take the grip off...there's one screw right in the center of the grip...undo that and don't lose it.
- remove dustcover
- remove the little arm of the hopup adjustment (tiny screw, don't lose it)
- on the left side by the hopup, you'll see a tiny screw that holds the battery tray onto the body...remove and slide the tray back a bit and then off.
- in the magwell area you'll see 4 screws...undo these and take them out
- the rifle should now "break" in two...the front end should be able to come away from the body...you will need to tilt and slide it out...be gentle, everything's plastic. Really...since you're just removing the mechbox...you just need to move the front enough so the nozzle of the mechbox clears free. WATCH out for the 4 nuts that those 4 screws attached to...on the kraken they have a habit of falling out of the front end. There's also a little spring in the front end/body for the charging handle rod that pushes on the dust cover latch.
- the mechbox should just wiggle/lift straight out of the body.
You want to take the little wire that came out the back of the body and reroute it so it goes up the left rear side of the mechbox and then ends with a plug at the back top of the mechbox...long enough so there's enough play to plug in a battery...not so much that you can't close things up because of of a big ball of wire.
- you can either extend the existing wire by soldering on longer wires...or run new wire.
-- do not just cut it and twist/electrical tape on some wire....strip, solder, file to shape, shrink wrap.
-- do not use junk wire (although the wire in the kraken is lousy to begin with). Plain hobby wire will work, 22AWG will fit for sure between the mechbox and body, 18AWG will probably fit too. 16AWG might be too thick.
-- mini connectors are available at airsoftparts.ca or at hobby stores...match it to your battery/existing config.
Reassemble pretty much in reverse order.
So....sounds complicated? It's not really if you have a good space to work on, the right tools/wire/connectors and patience.
If it really sounds daunting...find a local gun doc and ask them to do it for you.
Best of luck,