**We are happy to read these interesting and useful informations in the community** ;-) 

If you want to cross post, you hit the 3 little dots under the post and select *cross-post*, then the post will be shared in the community but you won't get any reward, as far as I know, 
>Rewards are automatically declined for the cross post and discussions under cross post will be different and will follow different community guidelines.

so my advice is to post *first in the right community*, **where interested-in-the-subject-people will read and upvote your post**, and only after cross-post it elsewhere.....
Of course you are not always aware of all the communities available, but you can always cross-post an old post of yours, and as written above, the rewards will be declined ;-)
Hope that helps