guys how can you write what you think in code? try to help me please

Question

i'm really impressed to see what some peoples are making in code playground, but i'don't understand. how all of you can write what you think a code? the tutorials in solo learn are good but are few it's basic data input and output.
'i'm trying to make a slide but i don't know how to write to java script to change the images everything that i learned was basic like if user type one thing i show some other thing with switch or if/else statement i'don't learned how to do the kind of interation with user like this

Answer 1

Iam learning in w3schools more turorial and example there.