Just get on with it man.
Take your cooker and your gas fire and demonstrate your competence to yourself. Some here were worried about you; just for the record, I'm not.
I can only get on with the job once I consider myself "competent" for the task at hand. For that I need to know the relevant pipe bore size to match the appliance load (i.e. the amount of gas it needs for it's Kw rating) and also if the run lengths and number of bends in my current gas piping are suitable for this layout.
This forum is driving me nuts. There is so much knowledge on here and so few people willing to genuinely help out. They would rather be rude and make it more awkward than it needs to be. You're one of them.