Is there a way to get this working on PM3.0 booted on riivolution?

I've gone through tutorials and I'm still unclear as to what the rudimentaries are for hacking brawl. I'm using riivolution to hack brawl. I have been able to run PM3.0, but I want to know if I can replace existing textures within PM with ones I find in the vault.

On another related question, how can I set up different mods on my card? Be able to boot up my Brawl with new characters, and also have PM3.0 as another option on Riivolution? I know these questions seem obvious and the info is somewhere on here, but for someone that just started hacking their Brawl 2 days ago, it's not as obvious. I've attempted a genuine effort to search the info myself, but I can't find it since I don't know the terminology. I don't really know what I'm even looking for. Any help will be greatly appreciated.

Hi, I just started playing PM 2 days ago, installed without any problems using Riivolution as my SD card is 32gb.  I have a few questions that are not intuitive to someone new to the community, and at the same time aren't explicitly answered by the FAQ and install guides. Namely, what is the process for installing the CEP or new characters to my current PM folder? I found a link here https://www.mediafire.com/?bbxweb8wled1bki that has a patch for PM3.0 to add some stages. Inside, it has instructions to delete entire folders and files within others. Once I applied the patch, my game would show the stage for example of Skyloft, but when selected it would give me the annoying stage with the fish bouncing off the leaves. For Hyrule Castle, it would give me Bridge of Eldin. Am I doing something wrong?

Will this also make adding entire new characters impossible? I found plenty that I would like to try out, such as Shadow Final.

https://www.youtube.com/watch?v=LQCmLkHjkWI This link also shows a heavily modded version, I have no idea how they got Tails, etc to work. Will I also be able to do this? Will I be able to add more stages than base PM3.0 provides? I know this is a lot, and probably really dumb questions and I'm familiar with pc game mods more or less, but the specifics of this I'm not familiar with. Any help will be greatly appreciated.