Dosing dextrose in the primary

[BeastMaster]

I'm going to be brewing a batch of Jester King Black Metal Imperial Stout tomorrow and the recipe calls for over 2 and half pounds of dextrose added to the primary. It states to begin dosing dextrose after 4 days in primary. How many doses should I do? I just dissolve it in boiling water, right?

 

[BeastMaster]

I'm just going to do seven additions over the course of two weeks.