Does anyone know any websites or apps that i can use to plan my lego motor cars before i build, so that i can get the main idea down first before i start, it would be nice if it was free too, thanks!

The typical choice these days is Bricklink's Stud.io program, which is a good program for virtual prototyping.

Welcome to Eurobricks!

I agree that BrickLink's Stud.io program is an excellent 3D LEGO build planner.  Using Stud.io, you can build, export parts lists through BrickLink Wanted list, and generate fairly logical/intuitive building instructions that do not require lots of graphic design if you plan your build steps well.  It is also free to download.

I've used and continue to use Stud.io to make custom sets and building instructions for gifts for my nephews as well as prototyping larger MOCs and checking parts for fit in specific designs.

Is there a so called play button or so, to see what your technic pieces could sonic real life?

56 minutes ago, ilovemakinglegorcraceonyt said:

Is there a so called play button or so, to see what your technic pieces could sonic real life?

No. It is not a Technic specific program and no mechanism can be tested virtually. Imho you should not design a Technic MOC virtually without building and testing the mechanism IRL 

I think you’re possibly trying to run before you can walk.

like your other thread I’d suggest you look though some official Lego instructions to see how Lego do things. If you’re after powered cars take a look at the top gear car and the new Audi etron for examples of how they do it.

stud.io is a good computer building tool but it doesn’t do any virtual testing for you, the only way to see if things work is to build it in reality

as Others have suggested also start with basics and slowly build up

the one thing I’ve learned with motors and gears is they often need a lot more bracing than you think to ensure gears don’t slip/skip