I have the private key.
Download Electrum (
https://electrum.org/). Create new wallet. Write down 12 words. Under the Wallet/Private keys menu, Sweep your private key.
Keep in mind that sweeping creates a transaction to transfer the coins to the wallet you (just) created. This means you pay the miners' fee.
If you want to just recover your wallet (and you're sure the private key was kept safe) you can just restore your wallet in Electrum on the "use public or private keys" path.