How to build a raised garden bed with seating?

[nvelaga]

Hello experts, 

I am total beginner and planning to step up my DIY journey.  

I am planning to setup a raised garden bed with seating options in couple of places. Along with it i am planning to install part of my back yard with decking ( deck with will be partly on concrete slab ). I have attached my plan and the sample raised bed i am considering. 

I am looking for suggestions on how should i plan the project , tools needed and procure materials ? I am finding lot of information over internet and its confusing. 

Thanks in advance