Welcome - I won't tell you it's hard...you've already found that out. +1 on Skreech's comment about choosing an MTL tank. I, too, used the Nautilus 2 to start, and believe it's a great choice. I've gotten family members and friends to quit with that tank since I have. You're trying to replace cigs, so IMO, it's best to choose something that'll help do that, rather than giving up cigs and trying to learn to DTL and be satisfied with that at the same time.
Haven't seen too many mentions about the juice, but I believe that's just as important as the equipment. I'd highly recommend getting a good tobacco juice. Hard to say what would work for each individual, but Halo Tribeca and Indigo Duke worked pretty well for me for the first couple of months. Now I know there are even better ones out there. You might try a popular NET (naturally extracted tobacco) like something from Heather's Heavenly Vapes, or N.E.T. Others will have suggestions for you as well. Do a little googling and see what sounds good. Don't be afraid of the nic...start high - something like 18mg or more to help you get started (less if you're sub ohm'ing and DTL).
For me the first couple of weeks were pretty rough, but I just said "I ain't going back," and stuck with it. Most of the day can be okay, then you might hit an hour or so when you just can't seem to hit the vape enough. But it does get easier, and pretty quickly after that first rough patch. In no time, you'll find yourself wanting the vape instead of a cigarette. Just stick with it, and it'll come. And fyi, I smoked over 45 years. Quit a few times. Tried vaping back around 2010, but equipment and quality was nowhere near what it is now. Just quit again in April. After 3 months, I tried a cig just to see, and it tasted ok, but was really pretty nasty - you can feel all that garbage in your system. It gave me a headache the rest of the day, and I haven't had one or wanted one since since.
Lots of people will be here to help you - just ping them with any questions, and you'll find all the knowledge and support you could want.