First off, congratulations on finding what appears to be a very complete specimen. While I have no idea about the interior of your car, the exterior looks to be in pretty good nick, with all of the lights, lenses, windows, trim and mouldings in place. You can safely assume that any problems that you might have faced in the eventual rebuild, have been halved JUST because your car is complete, and you won't have to do any running around for missing parts.
Next thing, please sit down and ask yourself the way you want to move forward. Basically, you have two options: to restore, or rebuild. If you want to restore the vehicle, you'll be looking at returning all things to genuine OEM specs, including the stock engine, transmission, brakes, drivetrain, and other assorted bits and pieces. If you're "resto-modding" it, you'll have the option of using aftermarket parts to bring the vehicle to your desired specs.
Also, it would be a good idea to determine what you WANT from the vehicle. A lot of people bung high performance engines into such cars, and grow disillusioned with them later, because they're not cheap enough to run on a daily basis. Conversely, some others keep it simple and straightforward, and grow fed up of the car later, because it isn't "quick" enough, or "nimble" enough. Please do give serious thought to this aspect beforehand, calculate how much money you're planning to spend, divide all aspects of the planned build into "essential" "desirable" and "non essential", and stick to your plan. Sudden random deviations from a well-thought plan of action can result in unnecessary expenditure, time delays, and heartburn. Also work out the logistics beforehand, carefully. Sit down and ask yourself, who is going to build the engine? Where do you source parts from? What painter are you going to use? How long are you going to wait for the finished product? And a billion other questions that will allow you to formulate that all-important action plan I mentioned earlier.
Next, brainstorm your OWN idea with friends, family and fellow enthusiasts. If you simply listen to everyone who offers you an idea/opinion, you will never get very far. Allow them to add to your own thoughts, rather than become the basis for your thoughts. To be honest, things like engine choice, colour, upholstery, exhaust pattern, brake modifications and the rest...can easily be decided before you take the plunge.
Best of luck.