I need help fixing how to compile EA without encountering errors.

'extern' - semicolon expected 60 1

'OnTick' - function was not declared as export4 65 6

'time_start' - undeclared identifier 69 16

'time_end' - undeclared identifier 69 37

'OBJ_TYPE' - undeclared identifier 74 33

'ObjectGetInteger' - no one of the overloads can be applied to the function call 74 13

'OBJ_PROP_MODE' - undeclared identifier 77 33

'ObjectGetInteger' - no one of the overloads can be applied to the function call 77 13

'ObjectGetInteger' - no one of the overloads can be applied to the function call 80 31

'ObjectGetInteger' - no one of the overloads can be applied to the function call 81 29

'ObjectGetDouble' - no one of the overloads can be applied to the function call 87 23

'ObjectGetDouble' - no one of the overloads can be applied to the function call 88 22

'j' - variable already defined 118 22

'prev_candle_high' - variable already defined 120 24

'prev_candle_low' - variable already defined chatgbt.mq4 121 24

'ObjectGetInteger' - no one of the overloads can be applied to the function call 136 44

'ObjectCreate' - no one of the overloads can be applied to the function call 140 13

'open_price' - variable already defined 170 20

'slippage' - variable already defined 171 20