I see some problems with the reference image, besides not matching in height, the side view looks orthagonal (good) but the front view appears perspective (not so good.) You can scale up the front view to the correct height, but don’t expect good matches.
As to modeling, either extrude a tube or cube to the entire length of the critter, then use the loop cut tool to cut in edges to push around, or extrude section by section, shaping as you go. Either will work. As soon as you have a rough shape of the legs, torso and head, cut a loop right down the middle, delete one half, and mirror the remaining half. Ignore the assymetry until you have the symmetrical parts modeled.
Regarding your image: to get better advice, post wires in front and side, orthagonal, not perspective renders at 3/4 view. It’s tough to give specific advice when we can’t see the mesh you are working on.