I'm a native spanish speaker. This translation looks perfect to me, with a very minor exception; "agregarlo" sounds more like south-american spanish. We would rather say "agregarle" in Spain, even though both ways would be understood.
"Agregarlo" would be correct if you are referencing an object (it's a 'loísmo', using -lo instead of -le when referencing people).
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Also, in Spain we refer to 'snowboarding' just as 'snowboard' (for the snowboard itself and for the activity)