doc: add instructions for starting fullnode with pbss (bnb-chain#1977)

README.md

@@ -150,7 +150,14 @@ unzip testnet.zip
 Download latest chaindata snapshot from [here](https://github.com/bnb-chain/bsc-snapshots). Follow the guide to structure your files.
 
 Note: if you can not download the chaindata snapshot and want to sync from genesis, you have to generate the genesis block first, you have already get the genesis.json in Step 2.
-So just run: `geth --datadir <datadir> init ./genesis.json`
+So just run: 
+``` shell
+## It will init genesis with Hash-Base Storage Scheme by default.
+geth --datadir <datadir> init ./genesis.json
+
+## It will init genesis with Path-Base Storage Scheme.
+geth --datadir <datadir> --state.scheme path init ./genesis.json
+```
 #### 4. Start a full node
 ```shell
 ./geth --config ./config.toml --datadir ./node  --cache 8000 --rpc.allow-unprotected-txs --history.transactions 0