Hello guys I'm new in the arduino world , I saw some project and I got very excited , I want to build my first project , engine starter through android watch , I wont ask for codes or anything I will try everything my self but I want someone to tell me how to get started and which components I need to buy . Thank you for your time .
Forget components for now.
Start with a Uno and the examples in the IDE to get familiar with the language and layout of a sketch
Your proposed project sounds way too complicated with your current level of knowledge.
What kind of engine? Mobile or stationary?
It seems like most of the work is on the Android side. Is that going to be difficult for you?
If - as I suspect - you mean remotely starting your car engine, then the general trend of this forum is to advise against it due to the substantial safety and insurance risks.
Cars are hard to modify yourself unless you are very careful! What you are talking about is possible, though you need to be sure that what you are doing is legal and safe (police get suspicious when they find strange devices attached to people’s car’s computers, apparently there are laws against it). At most, you will need a Bluetooth shield to connect your android to, and a relay to bypass the keys. This is a cool project, but remember that someone could steal your car is they got your phone or hijacked the arduino!