This is the best video I watched. There are many others that get into other details. Grab a pen and pad and take notes.  How to Grow Microgreens from Start to Finish (COMPLETE GUIDE)

To grow the greens I used a few supplies.  
Growing trays.  You want two types, both sized 1020.  One with holes, one without.  This allows you to water from the bottom.  10 Plant Growing Trays (with Drain Holes) - 20" x 10" - Perfect Garden Seed Starter Grow Trays: for Seedlings, Indoor Gardening, Growing Microgreens, Wheatgrass & More - Soil or Hydroponic
Grow light:  Give your plants light.  Hydrofarm FLP44 T5 Designer 4ft 4-Tube System w/bulbs  Many other options available.
Timer for the light:  I heard 18 hours of light is recommended.  Worked for me. 
Soil:  I used coir.  Fiber Soil (12 Quarts) Organic Potting Soil + Hydrating Bag = Healthy Plants. for Planting Indoor Container House Plants, Seed Starting, Herbs, Succulents, Wheatgrass, Microgreens | Easy-to-Store.
Scale (optional):  Many websites have the amounts needed for types of seed.  The point is to measure out enough seeds to cover the soil in the tray to make most use of space.  The websites break down how much weight of a certain type of seed you need for a 1020 tray.  I just eyeballed it.  
Seeds. Look for what you want to grow.  This is what I used for my first grow.  https://www.amazon.com/gp/product/B015V939EI/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
it says the seeds aren’t available.  Don’t worry, plenty of other types are available.  We liked the flavor of these. They go with everything.  
That's about it.  Don’t think too much about it.  Lay and pack your soil.  Spread your seeds.  Spritz them down.  Lay a tray on top. Weigh the tray down (I used a paint can).  Wait three days.  Remove covering tray.  Water every other day.  Harvest after a week. 
Try looking at growerssupply.com for materials as well.  Their prices look good.