I dont understand how to do substitution proofs without numbers.

It dependproof what is given in the proof. The first thing you must do before anything is to create a statement column & a reason column. The statement column will have all of the statements that are given to you as well as the ones you arrive at through the geometric principles you know. The reason column will least the reasons for each statement. You either put in that column "given" or you must put a geometric principle used to arrive at a certain statement.