hehe, well it wasn't that complicated really, in one sentence I would say I took the inside of one clock and put it into the other.. but in a bit more detail:
first I pulled apart the ikea dekad clock, and took everything out from inside of it... then took the back off the electronic alarm clock, removing the circuitry and stuff. my boyfriend helped cos I managed to break some of the wires going to the circuit, and he resoldered them back on for me...seeing as I don't really know anything about electronics. He also cut the board where the alarm functions were, because I didn't really want those, and the circuit wouldn't fit into the dekad clock otherwise. the glass from the front of the dekad clock was spraypainted black, leaving a rectangle clear(with masking tape) for the clock display to show through. the body of the clock was spraypainted with white gloss paint. then put the circuit inside and that was basically. oh and the electronic clock I bought had to be run off a powerpoint, couldn't just run on battery, so the cord was inserted through one of the holes in the back of the clock left from where the original clock had to be wound up. but i guess it would've been better to have gotten a clock that could be run on battery, as everytime I unplug the clock, the clock resets, and I have to open it up to set the time again. I also accidentally broke off the wires from the thingee where a backup battery can go (which saves the time but doesn't actually display it,) otherwise I may have put a backup battery in. I may still get my boyfriend to resolder that back on so that i can use it.
anyway hope that made sense, i'm not really very good at explaining stuff really.