Noob question about federation and communities

On my main (@[email protected]), I moderate [email protected]. I thought I’d kinda federate my existence on the platform by creating this alt on lemmy.ml, but when I search communities, while I can find some other lemmy.world ones (validating that .ml/.world federation is working as I understand it), technicaldeathmetal isn’t found. Am I doing something dumb as a user? As a mod? Have I misunderstood the intent of this instance, and I’d be better off trying the same thing from elsewhere? TIA