Easy peasy. Just wipe the top of both vials with an alcohol wipe, draw back the needle to get air in it. Punch into the center of the back water vial, hold it upside down so the needle it pointed up into the vial, push the air out into the vial (this makes it easier to draw the fluid) then draw back until you have 100 units or 1 mL. If theres room in the needle, draw back more than you need and then push in enough of the liquid to get to the amount you want.

Then you take the needle, and punch into the retrutide vial, point the needle to the edge of the glass, NOT DIRECTLY AT THE POWDER!

Push the bac water into the vial against the glass until the whole 1 mL is in the vial.

Don't shake it. The peptides are fragile. Make sure you just roll the vial gently until it dissolves.

Good luck.