You can define variables or placeholders in your TEAL program. During compilation, the IDE will ask to input values for these variables.
The variable name should always start with a prefix VAR_TMPL_ .
Example:
#pragma version 2
int VAR_TMPL_AMOUNT
txn Amount
...
...
In the above example, when you compile the TEAL program, you need to enter VAR_TMPL_AMOUNT variable value. The IDE automatically detects all variables start with VAR_TMPL_ and asks the user for the variable values if required. The IDE then creates the final source file in build/generated_src folder and then compile the final source file using the configured compiler (goal or Algorand node).