Well, as for the beginner i would strongly recommend to go first to some skate park and watch other guys how they on bmx perform tricks. If you are not sure ask them to repeat that trick so you can observe hot to do it. Second, watch a lot of youtube videos (maybe better step to start) where you can also observe bmx tricks how they can be done, and also you can see experienced BMXers what they choose form the street objects to use so they can perform tricks.. The trick with Freestyle ride is to have your route on the street where you will know exactly where is a bench, stairs, handrail or trash can so you can use them for your street performance.. Maybe is not a good idea to start playing bmx games, this website is good for example: www.bmxgames247.com
where you can find a lot of bmx games with freestyle ride..