A basic system includes 4 components:
(1) a tower antenna to collect the signal from the cell tower;
(2) a signal booster to amplify the signal;
(3) a device antenna to broadcast the amplified signal throughout the interior of a building to be used by devices, and
(4) coax cable to connect the first three components.
To determine if a wireless signal booster will work for you, go outside and make a call. If you cannot complete the connection because of weak signal, move to another side of the building.
When you find a location where you can successfully make a call, this side of the building is where you should place the tower antenna. If you are receiving a strong enough signal to make a call outdoors, the signal is probably strong enough for a booster to amplify the signal for use inside the building.