For the description or ad content, you should group these terms into several sub-groups so that the description can be written for each sub-group.
For the ad campaign, you select a single or multi if you see it fits. The ad campaign contains multi ad groups which are your sub-groups.
You can dynamically insert KW's into the ad's description as well.
I haven't seen any instructions or any guides on how this is done. Probably because AdWords developed this for the accounts THEY manage (large scale).