i'm trying to setup a proxy in android phone

the phone is rooted... and install ProxyDroid... but how i access the proxy server now? is the ip and port i setup in the app? cause i try that in my Instagram Bot and its can't connect... i feel i'm missing one step...

If you can offer a couple of screenshots of the proxy app, maybe we will assist you better.

On your mobile device tap Settings -> WiFi.
Long tap on connected network's name.
Modify Network Config -> Show Advanced Options.
Type the Host into the Proxy host name field and the Port into to the Proxy port field. ...
Click Save in the settings dialog. ...
Continue with Install Certificate procedure.

You can't easily host a proxy on your phone and access it.

You need to do a ssh tunnel to a server.

You could do it in theory over wifi but if you connect via wifi, your phone will use that for internet.