I have used Alaska Fish Emulsion before in soil; it worked OK. I followed the directions on the back and adapted as the plant responded. I still use Alaska Fish Emulsion on my outside herbs, such as mint and thyme. Today, I prefer to use Earth Juice. I have used it in soil with much success and am currently trying it in a DWC with what appears to be a excellent grow. It is more expensive, but worth every penny.
When using Alaska Fish Emulsion, I simple put the desired amount of fertilizer in a 1 gallon milk jug, shake, and pour. As with any organic fertilizer, you can let your mixture sit for 24 hours before applying.
Good luck with your grow.