From the site... (it's easier than it sounds)
Car Setup Page and Practice Laps
For each race you need to tune your car to a particular circuit. Fast circuits need low drag settings, and bumpy circuits need more supple suspension. Check your engineers report for initial advice. When you are ready to drive your first lap, click on TEST.
Driving Laps and Fine Tuning
Each time you take to the circuit you will gain more information about the car and which parameters you need to change. The ideal setup lies somewhere between the indicated "lo" and "hi" values. By positioning the slider for each parameter within this range you can fine tune your setup to perfection. The biggest performance gains are usually made within the first few laps.
You can control the amount of information you get back from a lap by adjusting this slider. Be warned though - pushing too hard could result in an accident!
You can access your team mates setup at any time. Use Team Talk to collaborate on setup information to make the most of your available laps.
These parameters apply to your behavior in a race. There are usually two parameters for both dry and wet conditions. For instance, you can decide to take it more easy in wet races, or perhaps push harder because everybody else is being cautious! It's up to you.
Overall Speed/Pace - The faster you go the greater the chance of an accident.
Aggression - If you are more aggressive it is easier to pass, but there is an increased chance of collision.
Tyre Use - If you give your tyres a hard life you will go quicker initially, but they will wear out quicker making you slower over a long stint. You should select a setting appropriate to your strategy or tyre selection.
Mechanical Sympathy - You can a little extra performance out of your car if you are willing to accept an increased chance of a breakdown.
Pit Stops - There are two sliders for driver and team. Cautious stops are slower but on the other hand there is less chance of somebody making a mistake and costing even more time.
Race Start - Choose between making a fast start or the increased risk of stalling or other calamity. Overtaking is easier on the first lap, so you may want to push harder if you are worried about being overtaken or simply want to try and make up for a bad qualifying session.
Qualifying is calculated automatically at the end of practice, and is a better indication of true performance than practice. Of course, it also decides the race grid.
You can decide which tyres to use for qualifying and how hard to push. If the race series you are in allows more than one lap for qualifying, it is recommended that your first lap is taken easy.
Some race series also allow you to decide when to take to the circuit. Generally later in the qualifying session is faster, but there may also be an increased chance of getting caught in traffic.
Like qualifying, the race is calculated at the end of a live warmup session. If the race weekend has mostly had consistent weather it is likely that everybody has good setups - so having a good race stategy could swing a race in your favour.
Choose your starting tyre, the number of pit stops you want to make and on which laps. This is fairly simple - just make sure you don't pit at the same time as your team mate!
Dealing with Changing Conditions
If it rains you need to decide which tyres you want to be on. Set the sliders to control the suitability of each tyre for wet or dry conditions. A checkbox allows you to omit some tyre choices from your race programme entirely.
A "changing tyres" slider controls how readily you will pit to fit different tyres if the weather conditions change. Pitting too often to change to more suitable tyres will always give you a faster car overall, but you may lose time overall with too many pit stops and being stuck behind traffic.
You can also configure your reaction to yellow flags, by entering the number of laps within a scheduled pit stop where you will reschedule it because of the yellow flag. Pitting under a yellow flag costs less time than when everybody is racing at full speed, but if you do this too far away from a scheduled pit stop you may be faced with driving a car very heavy on fuel.
The Order of Play and Race Results
Generally most races start with a live practice session, culminating in qualifying being calculated, and then a live warmup session, culminating in the race.
When the session advances you should receive an e-mail, and when you enter the game you can view the results from the link on the Office or News pages. The race results page features several analysis tools, graphs and maps and a means to watch or replay the race lap by lap.
Can you say 'Beer Can' without sounding like a Jamaican saying 'Bacon'?