Propane install

that doesn't really help.. I'm pretty good at building, I've done propane before too I just don't know specific code for vehicles, and don't know what fitting to get. so id ask here. I cannot afford to hire a person, I have to do 100% of it. I'm being told by different people I need rigid, other say non rigid, others say 100% copper lines. Im going to Home Depot tomorrow and will ask around, I'm not actually hooking anything up yet I just want to lay the lines down under the floor before I put the floor down for good. all I'm trying to figure out is the fittings/hoses needed, I will probably build my brass T.

basically, ill just have the propane lines laying under the floor ready to be connected when I figure out what I need. I always, always take the time to learn what I need but I am in a unique situation. the place I live I am not technically allowed a motorhome, or to work on my vehicle at all. the entire thing is in pieces in the yard, and I am VERY pressed for time. not to mention the tail lights/marker lights aren't even wired yet, and I know I should do it before putting the floor on but its one more thing I don't have time to learn at the moment. it sucks but it is what it is, ill have to do it afterwards tediously.