Hey, thanks for the feedback!
The gist for submitting a score is just to call
SilentWolf.Scores.persist_score(PLAYER_NAME, PLAYER_SCORE)
The yield I used on the tutorial helps us to continue running the code only after this function finishes what it has to do, and the rest of the things (the nodes, for instance) can be altered to suit the way you like to use Godot.
The important thing is to call SilentWolf.Scores.persist_score and pass the player name and the player score. For the player name, I suggest using a LineEdit node, and for the score, a variable on the global singleton should do the trick.
Sorry if my guide was a bit confusing, but I hope now you understand better how to send scores :)