sorry im thinking like some one with more experience....i am terrible at teaching but i can make a demonstration map much easier... i will edit this post with a link to the map hosted some where, sorry.
here is a Demonstration map i hope it can be of some help. the idea of the map is to use the SCV to build supply depots that in turn generate 10 minerals every few seconds.
Also feel free to drop by the Maspter Discord if you like. others there may be able to help better than my self.