Feel like an idiot!

I'm an intelligent woman, I really am. BUT maths terrifies me, I have a masters degree but numbers and me just aren't it!

With that in mind, despite having read all the beginners guides I cannot for the life of me figure out my dosing to start. I have a 10mg vial of reta and a 3mg BAC water vial.

I need to work out how to reconsitute it and what to draw to start on a 2mg dose

Are there any free apps that calculate this for me easily? As well as guiding me on cycles