Clarification on wording in The Foundations of Leninism?

Please delete or point me in the right direction if this isn’t the place for theory questions!

I’m currently reading The Foundations of Leninism, and under the section discussing the dictatorship of the proletariat, Stalin says,

“*In that Soviet power, by combining legislative and executive power in a single state organization and replacing territorial electoral constituencies by industrial units, factories and mills, thereby directly linking the workers and the laboring masses in general with the apparatus of state administration, teaches them how to govern the country.*”

The specific part of this that confuses me is, “**…replacing territorial electoral constituencies by industrial units, factories and mills…**”

I’m completely unsure as to what this part means. I understand the previous and following statement about a single state organization and teaching governance, however this middle section is stumping me due to the sentence structure/choice of words.

If anybody can shed any light on this, I’d appreciate it!