[solved] Libnss3.so missing in toolbox

Hi all,
Very new to Silverblue, and not really a techhead. I installed the xod ide in a toolbox, which completed okay. But when I try to start it I get a message saying libnss3.so is missing.
Solved this myself but sheer good luck. Now I’ve got a different problem. libgtk-3.so.0 missing.

Well, the same technique didn’t work this time. I found a .rpm file that looked like it was the right one, gtk3-3.24.8-1.fc30.i686.rpm. Downloaded and installed okay, but xod still produced the same error. So tried a couple more, gtk3-3.24.10-1.fc30.i686.rpm and gtk3-3.24.11-1.fc30.i686.rpm. Again installed fine but xod still fails.
How do I get around this problem?
Thanks, Ian