Using å and such.
Let’s say we want to use ü or ú or even û how would we do it?
option + n = ˜
option + e = ´
option + u = ¨
option + i = ˆ
By pressing any of those key combinations one of those symbols will appear in yellow. To use the symbol by itself simply press spacebar. To assign it to a letter that uses corresponds to that symbol such as ä you simply press the letter once you see the symbol in yellow.
What are our other options?

Regular Keyboard Layout

Keys available while holding the option key

Keys available while holding both option and shift
