If you haven't upgraded the GP H3+ Silver firmware beyond v2.xx then don't.
If you have, you have to downgrade it back to v2.xx. This will at least allow you to have a video feed again.
However, everything else will be manually controlled, on the ground, before you put the camera into the gimbal - start / stop, photos or video, etc. You will be able to point the camera using the gimbal but that's about all.
No firmware update provides full functionality on any GoPro model... yet...
Rumor has it that full functionality for the GoPro Hero 4 Black cameras will be available at some point in the future.
Best advice is to trade or sell your GP H3+ Silver and buy a GP H4 Black. I just did this and sent it to PeauProductions for a 4.35mm rectilinear lens installation.