Question

this is a question for testing anions,
I- and Cl-
a succesfull test was done, using these steps, add red lithmus paper to new sample, add AgN03 to new sample, and add dilute NH3. result CL- was found.
equations are:
Ag+ + Cl- gives AgCl-
Ag+ + 2NH3 gives [Ag(NH3)2]+
please can someone explain how the two equations arrive and balance.