First step, have a ethereum node running

ensure you have a node running on 8545 with contract deployed to it

then ensure you have a graph node running

setup a graph-node

git clone https://github.com/graphprotocol/graph-node/
cd graph-node/docker
docker-compose up

finally setup your subgraph

make sure you are in the subgraph folder, then

yarn

then generate code for graph

yarn codegen-graph

create graph

yarn create-local-graph

deploy graph

yarn deploy-local-graph

example graphQL query

{
  landSaleStats {
    id
    totalETHSpent
    totalDAISpent
    numDAIPurchases
    numETHPurchases
    numLandsFromDAIPurchase
    numLandsFromETHPurchase
    numUniquePurchaser
    numUniqueReceiver
    numNewUniquePurchaser
    numNewUniqueReceiver
    num1x1Purchases
    num3x3Purchases
    num6x6Purchases
    num12x12Purchases
    num24x24Purchases
  }
}