1.0 is newish and last I tried it (one of the beta versions) had bugs. I use 0.94 successfully so you might try downgrading to that. As noted by others any svg editor should work, Coral Draw is the choice of the person that taught me to make parts, but I have stayed on Inkscape because it is the most common here (and I’m used to its quirks.) This tutorial series may help, it doesn’t use parts editor (because parts editor isn’t completed) and assumes you understand xml though: