Not sure if you are RHD or LHD. for RHD, take out the pedals and seat. Form line to very accurate shape from old line. bend line gently in the middle so back and front can be passed through the holes in the firewall and rear pan section, straighten the line, fitting behind the seat track and tucking under the clips on the tunnel. Make sure the shape is right where it goes under the pedals. i know it seems like stripping half the car but I have tried to work around the seat and pedals in the past and it is hopeless, strip it out so 'the dog can see the rabbit'. Any way you can service your pedals at the same time, repair your clutch hook etc, which you have been meaning to do for a while!!
buy a tube bender too, brake lines can be done by hand but when you kink one you'll curse