First time applying a protective finish for a desk project

[nerdzcanbuild]

Hi there, 

I have been looking at projects where people have constructed their own desks. I have decided I would want to use the following benchtop: 

• Specrite 1800 x 600 x 18mm Golden Teak Acacia Multi Use Panel
  https://www.bunnings.com.au/specrite-1800-x-600-x-18mm-golden-teak-acacia-multi-use-panel_p0456515

Given what I have read I will be intending to sand down the panel and then put a protective finish to keep it protected for years to come.

I want to finish the benchtop for the best protection and from consulting different forums decided to use this: 

• Cabot's 250ml Gloss Water Based Cabothane Clear Polyurethane
  https://www.bunnings.com.au/cabot-s-250ml-gloss-water-based-cabothane-clear-polyurethane_p1520401

I wanted to check if I need to apply to the top and bottom all at once or can I allow one side to dry before flipping to apply to the other? I am limited with tools etc as I am new to DIY/home improvement in general.

Hope that makes sense and let me know if I have missed something or you need more information.