[Chimera-users] adding residues to N-terminal

Good days, I'm new user of Chimera therefore I need help using build structure option of program. I want to add MRAE residues to N-terminal of enzyme as an alpha helix structure but I can not use the directions of tutorial such as: addaa tyr,30 :29.a - add tyrosine in an extended conformation as residue 30, after residue 29 in chain A (the new residue will also be in chain A) Where can I write this command? I'm trying to add four residues to N terminal but I'm adding them to another point. I'm sending the screen image. Please help me. Best regards Dilara Karaman