Redirect https://

I bought managed wordpress and SSL certificate through GoDaddy. At first, they set up wp and SSL for me, so I had https:// address. but once I reset and re-install wp(using GoDaddy) my https:// address became just https:// They said I need a plugin within wp that will redirect my site to the https version, or I need to create a 301 redirect within my managed wordpress account in sftp. I tried my best but still do not know how. Please help me to have https:// address again. Thank you.