How i can build my own meshtastic firmware via platformio?

Hi, like the title says, how i can build my own firmware, i already downloaded vscode and put the platformio extension on it, is there a guide or something to build the firmware, i wanna modify it to send temp and humidity data from a mqtt topic, pls help

You should be able to use built in features for all of that. Look at setting up MQTT and the Environmental Monitoring plugin

do you ahve some links to how to build a firmware or even how to modify the MQTT to solve my problem, pls?