You're looking for a way to connect your karate with jujitsu. There actually is a very deep connection, one which you might not be aware of.
All of karate kata are based on classical jujitsu. I spend a good amount of time explaining this at the answer here:
Why is more time dedicated to exercises and very less for sparring? Is it for the fee?
That answer also links to another answer of mine giving an example of karate kata application / analysis (bunkai), here:
Name and meaning of stance where you stand with fists on hips?
Classical jujitsu training will teach you all of the stuff in your karate kata that you didn't know about before. You'll be able to just see it. And when you can see it, all of the previous explanations for what's going on in your karate kata will seem pretty silly.
Depending on who you are and what your ultimate goal is, this knowledge can either make you abandon karate altogether, or it can make you return to karate with renewed interest, focus, and respect.
Now, as for the differences in approaches to learning, this is where classical jujitsu is going to seem harder than karate, in my opinion. In karate, you learned your techniques by stringing each one together in the form of a kata. Each karate kata traced out a shape on the floor and ended at the same position as it began, so it was easy to remember. It made it easy to detect mistakes.
Karate kata were created as a mnemonic. They were created as a way of easily remembering sequences of techniques at a time when books and video weren't possible. They made it easier to preserve knowledge from generation to generation.
Classical jujitsu has its own kata. But those kata are typically done using partners. In classical jujitsu, the kata don't look at all like karate kata. Someone grabs you on your lapel, so you step out diagonally, then turn around and perform a hip throw, and finally end it with an elbow break with your knee. That's one kata.
The jujitsu kata are typically arranged in sections of a dozen or so kata. And there might be several sections to learn before you have the entire jujitsu ryu learned. Unfortunately, there's often no rhyme or reason for why each kata appears in a given section. Is the first section considered less advanced than the second section? Sometimes, but not generally.
So it's going to rely more on rote memorization to learn and remember jujitsu kata. It's very easy to forget a kata. You'll need to take good notes or video yourself.
Judo was actually one of the first jujitsu schools to organize their throws in a taxonomy from most to least useful. And when I say "useful", I mean these are techniques that have the broadest application in the most common scenarios.
Jujitsu kata are considered to be just a starting point. They exist to teach fundamental concepts. But they're often not very realistic for applying in a real fight. So most classical jujitsu schools have the notion of henka (variation).
You're expected to learn how to alter the kata to fit different situations without changing the fundamental concepts embedded in the kata. There can be many henka for each kata. You're expected to know the basic kata and be able to show its many henka.
Not only will jujitsu be harder to remember, it generally requires a partner to practice. One of the best things about karate is that it doesn't require a partner. You can repeat your karate kata on your own for however many reps you want. That lets you get good at it outside of your school time. You can't do that in classical jujitsu.
Another difference you're going to run into is the sparring. Classical jujitsu doesn't usually have anything equivalent to karate sparring. But this depends on the jujitsu school. Some may do a simulation of a fight, but it's usually constrained in a number of ways in order to prevent injury.
Punches and kicks will be the hardest thing for you to unlearn and relearn, unfortunately. The way classical jujitsu generates power for a punch or a kick is very different than what you learned in karate.
Most classical jujitsu styles come from Samurai battlefield arts. They assume you're going to be wearing armor on the battlefield. If you're wearing armor, you can't snap your punches and kicks out like you do in karate. Instead, you have to generate power gradually and smoothly, like a wave, connecting everything to a stance firmly rooted to the ground.
Striking in jujitsu will seem inferior to you after learning karate, at least at first. As you continue to learn and grow, you're going to realize that there are many advantages to the way jujitsu does it. And in the end, I think you'll add it to what you know in karate. They will become more tools in your toolbox.
My general advice for anyone trying to learn a new martial art after having trained significantly in another one is this: Start over from scratch. Keep whatever you think you know to yourself the entire time you're there. Even when you're warming up before class, you warm up the way they warm up. Observe everything and do only what they do. Above all else, when you find yourself struggling to perform things correctly, resist the urge to do it the way you were taught in your first style.
Empty your cup.
You'll be fine so long as you do that. It's going to be a big change for you, and that should be very exciting. If you must take anything into jujitsu from your karate, let it be the intangible qualities: discipline, focus, respect, and hard work.
Hope that helps!