Hola Waira
I'm so sorry about my late response, Tommy is on vacation and I have a new colleague who is still learning so I have a lot of work... Anyway, I will try to give you a complete answer to your question
I recommend you to make the decarboxylation before cooking the butter, in an oven. But, if the final butter will be envolved in a recipe with hot temperatures, it isn't necessary. If you make the recipe as shown in the video (cooking for 3 hours or more, at 105 ºC), the weed will be decarb'ed in this process.
I've used 10 grams of flowers for 250 grams of butter in a regular pot.
The last step is to press the cheese cloth when it is still hot to extract the mix of water/butter/trichomes in a recipient.
Then, you can throw the cheese cloth away and cool the mix. When it's cool enough, the water will separate from the butter (which contain the "power") and the butter is ready to use.
I hope this helps you but don't hesitate in ask more questions if something isn't clear
Big hugs!!
jaypp