Modeling sofa - problem with sewn parts

Hi,
I’m trying to model realistic sofa and for that I need to model also joined cover parts (see pic)


I’m trying to make it for 4 days now and still no idea. I was trying to do loopcuts and then push/pull edges but I got pretty bad mesh after subsurf. I was trying also to make seperate objects and then merge them with this armrest but it didn’t look realistic. Ripping edges also failed. Maybe someone had the same problem? Is there a fast way to do that? Maybe try to model mesh after subsurf modifier applied?

You could select the edges where you are wanting the seams to be then use the bevel command ctrl+b (Blender 2.79b) Then add as many edges and width of edges you want. Select the middle ones and pull them in on their normals.

I tryed to use bevel at the beginning but still - after adding subsurf modyfier it was a mess.
I’ve already found a solution in this topic:

Now I’m trying to figure it out