I used zero onions, as I wanted the sweet chlli type flavour from my soup.
Add all your ingredients to the soupmaker.
Top up with water, to above the minimum and below the maximum levels.
Crumble the stock cubes over the top, and mix well with a wooden spoon.
Make sure your lid in on properly.
Choose the smooth setting. I put this through my soupmaker twice. I did one cycle, then gave the soup a good stir before putting it on again. You can judge it by the results you get on your own version. I found it quite thick. I'd even be tempted to leave out one tin of chopped tomatoes in future, and add it for a second chunky setting for a more lumpy style soup, but I don't yet know if that would take my ingredients below the minimum line. I'll have to try it.