You can do it in the main loop or in a timed callback (by LVGL timer ) periodically. You’ll need to use lv_label_set_text_fmt function to get the numeric values read from the sensors into the labels. (If float-number support is needed in that function it can be enabled in lv_conf.h.)
( This similar topic might contain some more useful info: Add sensor data to chart (potentiometer, vibration, temperature) )