After recently purchasing our first home funds are low so we have bought old shipping containers of eBay that our carpenter has approved use for flooring.They are cedar wood and will be sanded and varnished, we would love a grey wash effect but are not sure how to achieve it....any advice would be much appreciated!!! The first pic is. what we have and the second is something like what we want to achieve (if possible) we realise that it won't be perfect but like the rustic look anyway!

After sanding the floors what step comes next varnish or painting and how to achieve the grey wash effect??
Thanks in advance :0)