Help with making plants

So I’ve been trying to make semi realistic plants for a scuba diving game I’m working on. But I’m pretty bad with modeling and don’t know how to go about this at all. Here are some examples from “Scuba diving at quill lake” of the type of plants I’m going for.
plantex1


plantex3
All I would like to know is how I could achieve making something like this.

Not a great modeler myself but Youtube is a mega help in these things.
You will most likely use the extrude and bevel blender options if I am correct.