Build Create, Needs to be better documented

Sorry for my English, I’m Brazilian, I’ve been using Drone for some time, however when I needed to perform manual builds I thought I could use the Create a New Build option. I went to the documentation, but it is very little explained, it should be built thinking about the users who started the Drone, I read it and didn’t understand anything. I tried to build my pipeline, because it says that the parameters will be passed as variables to the pipeline

My test: New Build (Parameter Key is text “TESTEKEY”, Parameter Value is text “TESTEVALUE”

  - name: Show Parameters
    image: busybox
    commands:
    - env
    - echo ${TESTEKEY}
    when:
      event:
        - custom

Can anyone share some usage examples? I think they would help a lot more than the documentation.