It's early '81 or earlier still (external door hinges), so it's correct to be fitted with drum brakes front. They should be the larger 228mm diameter ones.
In theory, and to some extent, they are self adjusting by the lever and ratchet under it on the first photo.
In practice I found that they will often leave the shoes a bit farther away from the drum than they should be.
The solution is to drill a 6mm hole on the drum face, roughly at a radius where the outer edge of the ratchet is. Note that on many drums the hole is already there (at least that's what is mentioned in the workshop manual).
Now by rotaing the drum and putting the hole on the correct position, using a screwdriver that passes throuh the hole you have two options: either loosen the adjustment, by pivoting the ratchet clockwise (anti-clockwise for the opposite side), or bring the shoes closer to the drum, by trying to push the lever towards the hub center. If the adjustment is loose, you will hear the ratchet clicking as you push the lever. If it's OK, you will not be able to push it further in, or the drum may lock, in which case you pivot the ratchet and start over again.
It's much simpler in practice than trying to describe it in words...