Twelve years ago I was, like you, a complete newbie in the realm of backpacking.
Like you, I enjoyed camping and long day-hikes.
Backpacking, I found, is simply joining the above two activities.
As other have said, the only way to learn how YOU can do this activity -- or even whether you want to -- is to just go out there and do it.
If you're as super-cautious as I was when I started, you can find YOUR level of comfort in the steps I took:
1) Drive to a nearby state or county park with overnight camping. Pack everything you think you'll need for backpacking. Park your car at a campsite, and then carry your pack ten meters from your car to the tent site. Then spend the night there using ONLY the stuff you've brought in your pack. The idea here is that NO MATTER HOW BADLY you've packed your pack, you're safe. Even if you forgot a decent sleeping bag, or tent poles, or matches, or WHATEVER; you know you can just get in the car and go home -- no harm, no foul. A great way to feel safe about step three.
2) Learn to pack, and then how to carry, your backpack; such that you can do so for an all-day hike. You can do this in your neighborhood, in a city park, or even on a day-hike that you've enjoyed in the past. You'll soon learn that one of the secrets of success is good packing -- and that includes getting rid of stuff that you don't really need. The other is ensuring that your footwear is comfortable for you after several hours of walking.
3) Do a true back-packing overnight, but only a few miles. If you've mastered steps one & two, this should be no problem. Again, the idea is to gain confidence in your ability to camp out with only the stuff you can carry for several miles.
4) The exercise I've found is most critical to getting in shape for backpacking is walking up & down steps -- learn to do so, repeatedly, for no less than 30 to 60 minutes. But start with no more than five minutes, and slowly build up your knee strength. Assuming you have good footwear -- and day-hikes should tell you that -- then your mission critical area will be your knees.
5) And finally, go out and do your first, week-long backpack! I GUARANTEE you won't make as many mistakes as I did on MY first true backpack.
https://www.whiteblaze.net/forum/ent...-the-Year-quot
And who knows? Six years from now you may well be giving advice to newbies on how to do that first backpack!