Adding strings to variables

In my game you can gain abilities so, naturally, I tried adding a string to my abilities variable like so:
*set abilities +",Life blast". Doesn’t work so how would I do this?

To combine or add to strings:

*set abilities abilities&", Life Blast"

This sets abilities to the current value of abilities + “Life Blast”

To do anything more complex or advanced than that I suggest you take a look at the extensive article on the dev wiki: http://choicescriptdev.wikia.com/wiki/Concatenation