@Chris H 's post is very accurate and informative... he summed up a lot of the things very well, but that's all it's possible to be - a summing up. No one from the outside can possibly know the details behind the figures. The "loans" could be any number of things. (If a director of a limited company puts his hand in his pocket to buy a screwdriver, he is "loaning" the money to the company to buy it.... for example).
The net book value of assets means very little. It will basically be a list of all the players, with initial cost, and a certain percentage "written off" against profits each year, for tax purposes. Most likely 10% or 20% straight line. When a player is sold, the profit is then based on the difference between their written down value, and the amount we sold for. (This is why the initial purchase of a player is a capital purchase, and doesn't go against profits).
FFP does not follow accounting rules. But the figures submitted to companies house, and the FA have to match.... so it's a balancing act between (legitimately) showing lower profits for less tax burden and higher profits for FFP spending power.
Lots of points not addressed here... and probably a bit rambling. I'm happy to try and answer specific questions if anyone has any.
(Also an accountant btw)....((with no real knowledge of football club accounts))....(((but I can try)))