Hi 
Hajin ,
I'm happy that this module could be a help! As for your questions, please find my replies as below:
1. Yes. you can enable EVAL mode and use MEM['index'] expression. But if you enalbe EVAL mode, you'll need to add double primes for each parameter. You can find an example image below. It's a tedious work and the reason why I disable EVAL mode in the begging. And please note that you'll need to use plus sign(+) to connect strings.
2. Yes. You can push <ctrl>+<enter> to add a line feed in editor. And you can see the last sentence of my example. The below image is taken from Openoffice. MS Excel uses the same combination key.
3. OK. If you want to pause <Typing> and <Scenario>, please add an new eventsheet and write the following codes(I name it e_pause_typing). After that, includes this new eventsheet in <e_AVG> of my AVG example. Then run the layout, push <P>/<G> keys on keyboard to test.