How to manipulate these constraints for 2-phase simplex method?

Question

I am trying to solve an LP problem with 3 constraints: $$x_1 + 2x_2 ≥6\\2x_1+x_2≥6\\ x_1 + x_2≤6\\$$ I understand that I need to change these constraints into standard from and add slack variables as well as another variable to make them equalities. However, I'm not sure what variables I should add to which constraints so that I can compute a feasible starting dictionary. One of my attempts was: $$\\-x_1-2x_2+x_3-x_0=-6\\-2x_1-x_2+x_4-x_0=-6\\x_1+x_2+x_5-x_0=6\\$$ Where $-x_0$ is being maximized and $x_3,x_4,x_5,x_0$ are variables that I've introduced in an attempt to make the constraints feasible.$$$$I tried to continue with the 2-phase method from here but I couldn't find get a correct optimal solution so I'm assuming I haven't manipulated the constraints correctly. Any help would be appreciated :)