I started writing out the whole schpiel below, which pretty much covers the basics of what I would have liked to have known when I started building coils. But then I did a bit more research on your mod, and the fact that it's cheap(no offence intended at all), from an unknown vendor, doesn't have variable wattage or any kind of display and the only safety features mentioned are "a safety cut-off feature for safety" doesn't provoke any kind of confidence.
So I would advise against building coils with your current set up and invest in a better/VW mod, but if you're anything like me, you're going to try anyway. So I've kept my original response in here(below), just be careful dude! and don't end up like one of those exploded battery face victims that the anti-vape community use as ammo.
[[You don't mention whether or not you have an ohm meter, and I don't see any indication of one on any images of the lite 40 mod that you have, so I wouldn't recommend that you start building coils until you have one.
If you do have one, then as the manufacturer of the Jomo Lite 40 suggests, you can go as low as 0.5 ohms, but I personally vape 0.5ohms at around 45-50W, so try aiming for 0.7 or higher.
So get some 26 to 28 AWG Kanthal A1(I'd recommend The Crazy Wire Company, as they're super cheap. google it, and don't bother with Nichrome, twisted or clapton just yet, due to lack of TC and 40W not being enough to heat 'crazy' coils quickly).
Then build and fit your first coil, while counting the number of wraps and leaving enough excess wire on the legs to add an extra wrap or two until you achieve your desired resistance(0.5ohm+ for single coil or 1ohm+ for dual). Keep in mind though, that the lower your resistance, the more watts you'll need to heat the coils and create descent vapor.
The rest is just trial and error while adjusting the ratio between wire and jig diameter and number of wraps.]]