Each subpackage is a separate module to minimize their dependency trees. To use the package you want, just import them using their respective package names - for example:
go get go.bobheadxi.dev/zapx/zapx go get go.bobheadxi.dev/zapx/ztest
Refer to the godoc for a complete listing of available packages and their functionality.
A few Makefile targets are available to help with development:
make mod # updates module definitions for all submodule make test # runs tests for each submodule
Refer to the Makefile for more details.