I have a variable +-10V DC signal, and a +-5V ADC range. How can I acquire the signal properly?

[Henrik_Volkers]

Luciana,

use a voltage divider. The simples form is build with two resistors. In your case two resistors of the (exactly) same value.
Connection is (Signal)-(Resistor1)-(ADCinput)-(Resistor2)-(SignalGround)
Depending on your DC Signal source and the input resistant of your ADC the value of your resistors should be in a range of from 10k up to 1M.
47k resistors are a good starting point 🙂
Since you said it is DC you don't have to care about frequency compensation.
Error calculation will be your homework