OK.... will try to answer your questions. Let's start with the first one.....painting straight lines. You do this by applying masking tape along the slightly raised line on the hull which indicates where the black "boot-Topping" should be. You then run another strip of tape a few millimetres below it. You can then paint between the tape. It doesn't matter if you paint over the edges of the tape because once you've finished painting you remove the tape and hey presto you have a perfect straight line. Make sure you keep the distance between the two strips of tape equal all the way as otherwise the line won't be even along the length of the hull. You'll notice I used normal sticky take on the Aircraft Carrier deck .....but it's far better to buy some low tack masking tape from a model shop. That way you don't risk spoiling your paintwork.
In order to glue the deck to the hull you will need to apply glue along the length of the hull and as soon as you place the deck in the correct position you use short strips of masking tape to hold it down. You stick a bit of tape to the deck and then run it down the side of the hull pulling on it as you do so. This will pull the deck down tight against the hull.