For Example, using the Insert Text Action:
You can (v7.2+) access a variable as if it is a comma separated array of text using the notation %Variable%
<VariableName>% where 3 can be any Calculation. You can use a different item separator by putting the text between the ] and % characters, eg %Variable%
<VariableName>:%. In v11+, the separator is processed for backslashes, so you can use %Variable%
<VariableName>\n% to get the 3rd line. Arrays are indexed starting from 1, and index 0 will give the count of the number of items, negative indices will index from the end of the array.
You can also use a short form of just %Variable Name% to include variables as long as the variable exists and has a value and there is no corresponding text token, although generally it is better and clearer to use the longer form %Variable%Variable Name%.