It's really simple. A plane is picked well in advance by the previous winner and the CM's create a race course (or select and possibly modifly an previous course).
Depending upon other events the terrain and course is ready in the SEA sometime after Sunday night for practise. A race description, and sometimes a course diagram, are available.
Monday sees many racers practising the course in the SEA throughout the day. If you have any specific questions, most of the racers will go over Start Procedure, race restrictions and rules.
At 10pm Eastern, after standard pre-race instructions (and possibly a course parade lap for familiarity and questions) racers are instructed to spawn at the designated base on a specific runway, with throttles back and engines shut off.
Upon command, racers start recorders (to resolve any race conflicts) and then engines and await the start command, give as a verbal and text "Go Go Go", and a tank cannon shot.
Courses typically involve flying around and between radar and water towers on the base and in the town, under city bridges, through one or more bomber hangars (one is usually the end the laps and the heat).
There are three heats per night in which everyone is eligble to race regardless of the outcoming of a single heat. Finish points for the three heats are totaled give the race winner and runners up. Individual Season anb Team points are given for the first 20 race positions - 1st place = 20 pts., 2nd = 19, 3rd = 18, etc.
All ordinance is disabled, and fuel loadout is completely up to the individual. This is usually a closely guarded secret and different for every race. With different planes, courses and number of laps (usually 3-5 laps per heat), a pilot must run the course in advance to determin fuel load. Unnecessary excess fuel will slow the aircraft down noticibly.
This racing requires absolutely spot-on fuel, throttle, engery and control surface management to win. Very good MA pilots come in to race and can get dusted for weeks until they learn the nuances of fine speed and turning performance.
And going through the first hangar without hitting the sides in the first lap of a heat can be intense as 6 or 7 planes try to go through at the same time.
And, have you ever had to race a Komet at 300+ mph inverted through a bomber hangar?
Can you?