1. Center sand strip:
You will need to make some soil dividers out of acrylic and silicon to bottom of tank to keep sand and soil separate. Dont do it exactly in the center. Look at the first pic you posted and notice how the landscape is divided into unequal thirds to give the scape balance.
2. Substrate.
Amano aqua soil works good and is packed with nutrients and requires little to no fertilizers. It will take a long time for the tank to cycle though as the Amano soil leeches out excess nutrients at first.
There is also "mineralized top soil" under the sand option, which is cheaper and works even better, but takes longer to prep.
http://www.aquaticplantcentral.com/...-mineralized-soil-substrate-aaron-talbot.html
3. Lighting
To keep grasses and HC growing low you will need strong lighting. Too many options to list.
4. Starting HC and hair grass
Many people will start growing their HC and grass in a terrarium environment first by covering the tank with plastic and then only filling with water once the plants have established a strong root system
5. Co2 injection
With the high light you will need to supplement ferts and Co2 to keep up with growth. You can go with an off the shelf Milwaukee unit, but they are cheap and prone to fail.
I highly recommend piecing together a quality unit. It will run you several hundred dollars but last a life time.
http://www.barrreport.com/forum/barr-report/co2-enrichment/6653-dual-stage-regulators
http://www.barrreport.com/forum/bar...regulator-part-numbers-sources-and-other-tips
Highly recommend
www.barrreport.com for a freshwater planted tank forum.