Just use the glue recommended to build plastic models with. They dissolve the surface of the plastic and weld the two parts together making is as good as one part. The plastic will break befor the joint. CA is just a glue that sticks things together and the bond is not that strong. (until you get it on your fingers). A good knock and a CA glued joint will fail.
Yu can also just use acrylic paints for the hull. Once they are cured they are quite waterproof.
Models specific advice: Go to a reputable shop, they should know the best way.
Bottom line as a first timer you will need three small motors, shafts and tubes. Possibly some brass propellers.
A radio sender and receiver. Four channels will be fine. you only really need two. One to control the motors and one to steer the rudder. All the others are extras.
If you want to buy a 32channel unit fine but you will still only use two or three chanels. lol
As others have suggested, join the forum as a supportere and open a build. You will not regret it and money well spent.