Step 1:

Add a proxy

Step 2：

Click on Apple logo at the top left corner > System Preferences > Network > Advanced

1. Click on "System Preferences"

2. Click on "Network"

3. Click on "Advanced"

Step 3:

Setting up proxy service:

Proxy > SOCKS Proxy > Local Proxy Address and Port > OK > Application

1. Select the "Proxies" then select the protocol "SOCKS Proxy":

2. Fill in your local proxy address and port:

3. Click "Apply": 

The proxy becomes operational once the previous steps are concluded.