I want to change camera with animation as I know it can be done with timelines but i have no idea what timeline really is so how can I do something like this or is there any other ways that will be easier?
To get a grip of what a Timeline is and does, I suggest to start reading this: Timelines | Unreal Engine Documentation
Timelines are good if you want to alter simple variables in a span of time.
In your case you can create a timeline that changes the Vectors of your Camera Transforms.
If you have in mind a cinematic scene with complicated camera cuts and movements I would suggest to investigate the Sequencer.
This is the tool to use to create “movie-like” in-game cinematics. With it you can alter pretty much anything in your Level.
Personally I like to use the Sequencer for everything that falls in the category of “cutscene” (eg. section of the game where the player is supposed to just look at the screen and enjoy.), while Timelines are best suited for brief variations during gameplay, when the player is in full control of the game.