As I am also building a 78. Sturm Division Unit I am in need of some trenches and stuff like that. The barbwire stuff from the BF webpage looked easy and I also would rate it as being easy.
Scale for this one is 20cm by 5cm. This is also the exact sizing BF gives on their webpage.After cutting your Balsa Wood into shape you can take some of your match sticks and cut them to approx size of a standing model. You will need three parts of your cut match stick for one "metal holder". So superglue them together (first as a cross and then do a support strand as the third one). This done you can either choose to do only one row of barbwire in the middle or two from the outside. As sticking to BF plans this one will focus on only one row in the middle.
Superglue your selfmade metal poles to the balsa wood. As I did it ... you can put in some variation on the wideness of your metal poles.
Take your miliput or similar epoxy to build some nice textures around (e.g. craters).
Use filler to give the balsa board some more texture.
Paint and flock as desired
Take your wire and a thin pen. Spin the wire around the pen and you get your barbwire rolls. Cut down as desired. Paint them as you like and as it fits to your scenery. and glue them to the board.
Enjoy your work