Articulations in Dorico

I can set a natural keyswitch for a Session Horns Pro instrument but I cant set a base keyswitch as staccato and than I cant find the word staccato to add it to the note

Are you talking about creating an Expression Map?

Staccato should be in the list of Playback Techniques when you create a Base expression.

Can you show us a screenshot of what you’re seeing?