cd /var/lib/astar/astar-db/polkadot/chains/polkadot
# if folder doesn't excist create and go navigate to the folder
sudo mkdir /var/lib/astar/astar-db/polkadot/chains/polkadot && cd /var/lib/astar/astar-db/polkadot/chains/polkadot
# download the latest snapshot
wget https://dot-rocksdb.polkashots.io/snapshot -O polkadot.RocksDb.tar.lz4
# extract snapshot (this can take some time) - make sure you have permission in the directory
lz4 -c -d polkadot.RocksDb.tar.lz4 | tar -x -C /var/lib/astar/astar-db/polkadot/chains/polkadot
rm -v polkadot.RocksDb.tar.lz4