If you want to grow the same exact rose from the plant you got your seed from, the best way is to take cuttings. If you grow from seed you may be disappointed in what you end up with. Here's how to grow roses from seed.
Here's how to propagate from cuttings.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.