I do both liberty training and clicker training. I would suggest that you distinguish trick training from liberty training. Tricks are usually taught using a technique like clicker training (which is a fairly easy concept to grasp - you can find tons of information about it online as you basically shape behaviors using a noise and then a reward). On the other hand, liberty training often does not involve food rewards. I also suggest that rather than cobbling together random amateur videos on YouTube to come up with a training plan for your horse, you find a trainer you like and pay for a course. It can be an online course, and does not have to cost a fortune, but it really helps to have it broken down into progressive steps from beginning to end. Otherwise, there is a risk that you will teach the wrong thing in the wrong order, and end up with undesirable behaviors.
The important thing with clicker training is timing. You MUST make the sound exactly at the right time. Giving a treat after the behavior is not specific enough - the horse won't know which part of the behavior earned the treat. But it's fairly easy to figure out and apply once you get the concept. And horses usually get it within a couple of sessions. First start with creating the association between the sound and the reward. This is easy to do, just click, then treat. It won't take long before they start to look for the treat after they hear the sound. I don't use an actual clicker for this, because I want to keep my hands free, so I cluck with my tongue (not the same sound you would use to ask for a trot, obviously). Then you start to shape behaviors. A good (and useful) one to start with is lowering the head. Apply pressure with your hand behind the ear, wait for the horse to lower its head even just a little, and the split second they do that, cluck and reward. In terms of other tricks, be wary of teaching behaviors you don't want. Asking a horse to "shake hands" can lead a horse to pawing people randomly with their hooves which can be very dangerous. Same thing with rearing which should be kept for professional trainers only. But clicker training can be a great tool for re-shaping behaviors into something that makes things easier too. For example, my young horse had a terrible habit of throwing his head up in the air whenever we tried to bridle him. It was a fight every time. So I used clicker training, and within a week, he was lowering his head and taking the bit into his mouth himself (I would cluck when the bit was in, then remove it, and treat, then leave it in longer and longer).
Liberty training is more subtle. To get the horse to follow you around at liberty, ie, without any tack at all in an open area, you'll need to learn to communicate with them in a language they understand. This is where following a trainer is helpful. To "speak" their language, you will need to start with some very basic things that will not immediately seem like they're related to liberty training, but they are all important steps in creating that bond. And don't forget that liberty training means the horse can leave at any time. You have to respect that, otherwise, it's not liberty. The trainer I followed would tell us that if the horse leaves your side, resist the urge to follow it to re-connect, and instead, go in the opposite direction. Like magic, this made my mare come back to me. Liberty training is also about being able to send the horse away from you, and bring it back in. Like an alpha horse that drives away another horse. Oddly, the other horse usually tries to come back, or stay close to the alpha horse even though it keeps driving it away. It has been absolutely amazing for my mare and I to do it, but it requires a lot of time and patience. Of course some horses will spontaneously follow you around - my new gelding does this all the time. But if I were to ask him for specific movements, he wouldn't have a clue what I'm telling him. There is a difference between a horse that is responding to your signals and one that is just naturally friendly and people-oriented like my goofy gelding. He wants to play and hang out, he's not actually paying any attention to my cues, whereas my sensitive mare that I've spent months working with at liberty will do exactly what I ask - starting, stopping, reversing, moving her hauches, her shoulder, her neck, all without me touching her. It's magical once it all comes together.