hmm...
If you have been doing it for 3 month, you still don't understand agile, perhaps there is something wrong with the project manager.
Generally, for a project to run well, for any process, you need a person accountable for it. That person should be the project manager (in small teams that person may wear multiple hats). His or her job should be make sure everyone understand the process and why (i.e. what are the benefits) of following those processes. If you don't know, then that person haven't done his or her job.
There are plenty of book and article on the details of running a scrum or kanban process. But at a high level, agile methodology is based on iterative improvement, while requirements and the software evolve as you go vs. the traditional waterfall approach, where all the requirement are defined before you code. Key benefit is that the theory that is really really hard to know all the requirement for software product ahead of time, it is better to delivery something and get feedback and iterate rather than "finalize" requirements and only to find out it isn't what the customer want.
Second question, what kind of project is suitable for agile process? Almost any project, but process should be proportional to the team size and complexity of the project. If you have only one or two people, too much process can be a blocker. If you have 3 to 10 people, scrum process can be good. If bigger than that, you can consider split into pods, where each pods is about 3 to 10 people. Each pods focus on one aspect of the product and apply the agile process,