If you can't find mylar, try a couple of coats of flat white enamel paint or a box of flat white linoleum. (the 'stick-on' kitchen tile squares)

Some folks love the Mylar, but I personally like not having to carefully clean overspray and dust off of it all the time. (can scratch, rip and crease fairly easily, too)

Not knowing what nutes you have access to, I recommend the Fox Farms or Botanicare lines. You'll want a veg nute, a flower nute and micronutes.

Do you have a way to check water ph? (ph pen works best) Soil checkers are a waste.

Placing your 4' fluoro vertically, you'll lose valuable lumens unless the plants are 4' tall. Try placing it horizontal, flat against the back wall. (if the interior dimensions are allow it) Sure wish the company that designed my home would have made my closets 48" wide, instead of 46". Then I could actually use the fluoro lights and fixtures I had for vegging, lol.