How to literally translate this 就是一进街口靠墙的一个小棚子?

Question

记得小时候，我家附近就有个小人书摊，就是一进街口靠墙的一个小棚子，里面用几块砖头支着粗糙的木头板子供人们坐着看书。

This is from the Standard Course Book of HSK5, chapter 20.

About the literal translation of this 就是一进街口靠墙的一个小棚子:

就是(was)一(a)进(classifier)街口(street entrance)靠(leaning against)墙(wall)的一(a)个小(small)棚子(shed)

I think I need much help to make it make sense. Why twice 一? 进 is a classifier (for the 街口) or it means in / into? I think I have perplexed all the sentence structure of [subject object verb adjective noun etc.].

Answer 1

就是一进街口靠墙的一个小棚子.

You can not translate 一进街口 literally, 一进 actually means "just/immediately entering". Here, "一" is not a classifier, but indicates a short moment of the action described by it, such as 一出來(just outside of), 一下子(suddenly).

一进街口 = immediately entering the street corner.