This is a fun little project to attempt now your Primula veris and P. vulgaris have largely finished flowering. They will seed themselves, but you might just wish to experiment with your own man-made propagation to see how well you do. Just be aware they can be a little tricky sometimes.
The seed is very fine and doesn’t need burying under compost – just leave it on the surface of moist compost, covered with a fine layer of grit, which gives light protection but room for seedlings to emerge from it. Once sown keep your seed tray at around 15C (59F) for germination, but be patient! It’ll take a while – up to six or so weeks – for possible germination. If it doesn’t happen in that time, give your seed tray a period of cold stratification – a few weeks in the fridge – and then bring out to the warmth again.
Once seedlings have grown and can be easily pricked out, grow them on in small pots before planting out in autumn.