This is a corrido about coming up from nothing, and it opens like a toast: "Ahí le va pa toda mi gente que viene desde abajo" (here's one for all my people who come from the bottom). Desde abajo (from below) is the phrase the whole song keeps returning to.
The story is plain and personal. He has worked hard since he was ten, "desde los diez años trabajé bastante" (since I was ten I worked a lot), and his dream was to help his mother. He thanks God for watching his steps and admits he took a crooked path out of need: "a lo chueco me metí" (I got into the crooked stuff). Chueco literally means bent or twisted, and in Mexican slang it means illegal.
Then the tone hardens. "Se mira calmado, sencillo el chavalo" (the kid looks calm and simple), but nobody should go looking for trouble. A 5-7 is a Five-seveN pistol, and "el tiro montado" (a round chambered) means always ready to shoot. Ruletear is slang for cruising around, here in a Dodge Hellcat, with Louis Vuitton shoes on. It is a bit much, and that is the point of the genre: hard work, loyalty to his compa (buddy) Chango, and a lot of swagger. Learner tip: pa is the spoken short form of para (for).