Mostly easy.....the names and most of the colors are just click and type or click and change the color. However, those round meters are a series of images. Each meter you see is made up of 16 individual images that AIDA show depending on whatever criteria you give it. So, you would have to use a graphic editor, such as Photoshop to change the colors, then update the 16 images (maybe more since there are large and small). Just click and modify what you want and all this will be more clear. Good luck!
Now, changing to vertical will require graphic work. Again, the background, those lines, etc are just a single image file. So, you'd have to do a lot of copy/pasta to change the layout....but again, easy if you have a basic understanding of graphics apps.