How to use force flask

I made some force flasks to collect some cows and sheep and I cannot capture an entity. I have tried right clicking on mobs, shift right clicking and clicking on them with a force rod. I'm sure I'm doing it wrong so i was wondering, how can i capture an entity in dartcraft?

 

You need a rod of holding (force rod, upgraded with a force flask in the force infuser). When you have flasks in your inventory and right click a mob with the rod, it'll capture them.