Download Electrum from this site
only:
https://electrum.org/#downloadImportant! Verify your download by following the instructions for your OS here:
https://bitcoinelectrum.com/how-to-verify-your-electrum-download/. This is to ensure the Electrum file you have downloaded is authentic and has not been tampered with. There are a number of fake/malware versions being spread.
Install and launch Electrum.
Create a new wallet, select "Standard wallet", select "I already have a seed", enter your seed phrase, and then set a password for your wallet. Done.