Hi, thanks. There are a few utilities people use to help create the command sent to steemconnect to process a delegation.
I use this:
https://helloacm.com/tools/steemit/sp-delegate-form/?delegatee=accelerator
Just fill in your steemit username as delegator and then the value in SP.
Then click "Delegate via steemconnect.com"
That will convert SP into vests (which is the underlying unit of "currency") and double check both usernames are correct.
Only at the final step do you need to enter a key - use either your active private key or higher.
That's it! :-)

I'll be here for another hour or so - any problems, send me a message/comment.