OK, so on cider kits. I actually have a cider kit at home busy fermenting, but it's a different one to what you have. I'm brewing a Mangrove Jack's cider pouch, but I suspect the concept will be the same.
Now, as with all kits, you bought a highly concentrated fruit juice with some additions. In my experience (so far, anyway), these kits generally contain crap yeast with no nutrients. While some say also that ciders and beers don't need nutrients, I still like adding some nutrients, specially when rehydrating the yeast.
These kits come out fine if you follow the instructions to the T (like, REALLY fine), but you can improve them by following a few simple steps:
1. Get proper yeast. Depending on your location and weather, pick a cider yeast that'll do best in your case. The "workhorse" yeasts that come in these kits are usually very basic, and not suited toward your specific cider's flavour profile. They're also quite old in most cases, and are not always well stored.
2. Rehydrate and feed your yeast. I rehydrate as normal, add some nutrients (Fermaid O) to the yeast when rehydrating and also condition the yeast a bit to the juice before pitching. I just like my yeast happy.
3. Give it time. It should be done in less than a week, if you follow it to the T, but don't rush it. My current cider took only 4 days from start to finish, and it was completely done. Leave it in the fermenter for at least 2 weeks, in my opinion. 2~3 weeks gives it time to mellow out, and allows the artificial sweeteners and flavouring packets added to the cider to "blend". It may not sound like much, but trust me, it makes a huge difference.
And that's about it. Enjoy - it's SUPER easy to make!
PS: That sweetener is saccharin. 600 times sweeter than sugar. Use that packet sparingly - if you want a dry cider, don't add it. Off-dry, add half that packet. Sweet, add the whole packet. DON'T add the sweetener until you've tasted the cider after 2 weeks in the fermenter - so you can make an informed decision. You can always add more sweetener - but you can't take any of it away.