I played book II first and when starting out I had no idea how to set a powder keg off. There is no mention of how to do it in the manual and there ought to be.

In book 1 I can find no way to pick up a powder keg and inventory it or move it.
Since I had read how to set them off here in the posts I knew how to set them off but can't move them as in game II.

Nope, you can't carry powder kegs in Book 1. That was a new ability that wasn't added until Book 2. So in Book 1, you need to lure the enemies to the powder kegs...