You get 1 race that you can organise in your centre without buying a race track which costs 20,000e - 80,000e so don't bother buying one untill your loaded. To get people to run your races you need a catchy name but something to do with running, you then chose either if you race is galloping or troting this choice is upto you. Then you need to click change parametres to change other information. You now chose the required galloping / troting skill level that a horse needs to run the race i would set this at about 0% ish which you can then rise slowly each day. You can then chose the breed to run the race you want to chose a breed that is normaly stared in galloping / troting so here are the breeds that would be the bet to chose.
Good Luck remember it takes time for you competions for get better.