Sow the seeds in March in a warm place. (February if you have a greenhouse/conservatory). Water lightly with a fine spray or mist generously.
As soon as the seedlings appear, uncover them, and leave them somewhere bright, so they’ll get sturdy. Water, if needed, as above. Don't overwater as they will become mouldy.
Pot these little seedlings up in small 7cm-9cm (3″-4″) pots with compost meant for seedlings. Place them in a bright place. Get grow lights if you haven’t got a handy windowsill.
Then, you just wait for them to outgrow their pots before repotting them. I usually do this twice more. When you repot the chilli plant, a lot of energy is spent on growing the roots, so planting up into a large pot too soon, can result in unhappy plants, as the much needed energy goes downwards instead of upwards.Water regularly.
Plant out in May, when the evenings are not too cold anymore. Water and feed regularly. I love Chilli Focus, just do a Google search.