for newcomers to training, there are two highly frequent and extremely similar movements that make them silly to distinguish. If they don't pay attention, they can't even tell which one they are doing.
These two movements are the dumbbell overhead row and the dumbbell overhead arm curl.

the dumbbell prone arm curl has a fixed large arm, but those with poor proprioception will unconsciously move their large arm to look as if they are doing a dumbbell row. This also shows that there is a slight difficulty in mastering the dumbbell dip arm curl.
As a really great isolation triple head move, you should definitely learn it.

what is the best technique for doing dumbbell dips and arm curls?
Starting movement: Stand next to a flat bench. Hold the dumbbell in a counter grip with one hand and the other hand and ipsilateral knee on the bench.
Hold the arm holding the dumbbell with the forearm bent at 90 degrees and the upper arm close to the torso, parallel to the floor (or even slightly above horizontal i.e. Elbow above shoulder), thus maintaining triceps tension. Bringing the elbow up slightly will help some of the guys to feel the triceps better.
Movement: Keeping the upper arm still, contract the triceps to extend the elbow until the arm is parallel to the floor. Squeeze your elbow outwards hard and then slowly return to the starting position.

other movement tips for the dumbbell prone arm curl
it is important to maintain the correct movement position while doing this movement to ensure the effectiveness of the exercise. If done incorrectly, it may lead to injury or failure to achieve training results. It is therefore very important for the trainer to perform the movement with the correct technique in order to achieve the best possible training results.
1. Movement path
holding a dumbbell in your hand, draw an arc from your shoulders to your hips as you extend your arms.

2. Points to note
keep your elbows on one side of your body at all times keep your shoulders and spine in the same plane at all times when lifting and lowering the dumbbells; your body may swing when lifting the load, making your lower back unstable and prone to injury. The longer you hold the contracted position (i.e. Arms straight) the better. In fact, unlike other triceps movements, this movement requires a lot of muscle tension to keep the arms straight.
3. Try to avoid
try to avoid elbows down or away from your side try to avoid shrugging your shoulders try to avoid turning your shoulders forward or your torso avoid throwing the dumbbells with inertia. Lift slowly and feel the triceps firing. Bench support your body and place one leg in front of the other, you should be able to isolate the triceps.

variations
1. Double arm dumbbell triceps arm curls. Do this movement using both hands at the same time. Bend over so that your torso is parallel to the floor, rather than using a bench. Keep the upper arms parallel to the floor and the elbows tensed at all times. Perform the exercise according to the method given above.
2. Rope arm curls. You can use a rope instead of a dumbbell. The main advantage of the rope is that it offers more fluidity than free weights.

3. Positive grip dumbbell prone arm curls. Use a square grip position with the knuckles down when lifting the dumbbells. This increases lateral hair force, although the difference is minimal.
4. Reverse grip dumbbell arm extension. The grip used in this movement is the opposite of the above variation, with the dumbbells being lifted with the palms down. This will increase lateral hair strength, although the difference is minimal.

5. Plank arm extensions. Lie face down on a flat bench, holding a light dumbbell in each hand. Sit with your legs across the bench, leaning your legs slightly towards the bench and touching your toes to the floor for stability.
Keep your elbows up so that your upper arms are in a straight line with your back. Arms should be at 90 degrees, elbows back, knuckles pointing towards the floor, palms facing in. Without moving the upper arm, slowly straighten the arm. Squeeze the triceps and then bend the elbows to lower the weight.

muscles to be trained
the opposite grip grip (thumbs forward) works all parts of the triceps. Rotating the dumbbells with the palms facing upwards will target the lateral head of the triceps.
Primary muscles: Triceps secondary muscles: Elbow muscles (rear deltoid, latissimus dorsi) antagonists: Biceps, brachioradialis

replacement movements
there are a range of training movements that target the triceps. The four triceps movements below are ones that every body conscious person should do. Efficiency and effectiveness are the deciding factors when choosing a movement.
Triceps double bar arm flexion narrow grip barbell bench press rope pull down seated dumbbell triceps flexion

only the elbow joint is active during the entire trajectory of the movement. Apart from the triceps and forearm flexors, the dumbbell prone arm flexor does not recruit more muscles to fire, so be sure not to spike the weight throughout the movement, maintaining good posture is difficult and important.