Well I'm similar I'm not exactly sure, but I guess pretty much that in the bottom left corner there are two indicators the arrows are where roughly your horse wants to be positioned early to gain more potential to win.
The second indictator is the speed control the green within this on the left is how fast your going by pressing UP to improve your speed this however causes your potential to start to drop. If a race is 2 miles I tend to start moving up through the race slowly from 9-10F from home this is displayed in the top right corner. Once I get to two furlongs then i press up more rapidly which increases your speed and starts to whip your horse.
In jump a races to start with i couldn't get jumping regularly using the indicators, that flash up too quickly in my opinion. I just try jump where I think the horse would jump from in real life. If your held up watching horses in front helps to work out the ideal jumping spot. Using Ctrl or Action button to jump.
More info on jockey controls below
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