Create a Steemit - Account, free and immediately available
In advance
Creating a new account with this method only works if you already have an account and have 3 STEEM (not Steempower) in your wallet.
If you don't have an account, ask a friend with one who will do it for you.
Here is a step by step guide.
Step 1, you need an available name for your Steemit account.
Just go to https://steemit.com and enter your desired name in the address line as shown in the picture:
Here is the desired name useful
This name is already used, because I am redirected to the page of the user.
New try with a new name useful.stuff.
This name is still free and so 
All I have to do is set up the new account.
2nd step, set up with Steemconnect
Go to the page https://v2.steemconnect.com/accounts/create
Username:
Your desired name (here useful.stuff)
Password
The password is generated automatically and you can't change it here. But don't worry, you only need it for the first login and to change a new password. So copy the password. If you lose it you won't get into this account and your name is lost to you.__
STEEM
Here you have to enter the number of STEEMs it "costs" to register the account.
_ Above I said this type of account setup is free and that is correct. These STEEM will be credited to the new account as Steempower._
To find out how much it cost STEEM go to: https://steemd.com/
There you will find the Current witness on the right side. Click on the name and scroll down the new page until you find the line "account_creation_fee 0.100 STEEM" in the box on the left.
You have to multiply this number, here 0.1 STEEM, by 30, here are the 3 STEEM, and enter it in the third field.
Make sure that you have 3 STEEM (not Steempower) in your wallet!_
Now you are done here (password is copied?),
The 4th field remains empty, unless you want to pay in Vests instead of in STEEM.
Click on Continue.
Well, that's the way it goes.
I write here several times that you have to copy the password and I forget it myself.
The name@useful-stuff.
After you click on Continue, you have to log in on the next page with your existing account!
If this has happened, you will see the empty form from before. Don't be frightened, your new account is registered. You can now call it as usual:
Last Steps
Log out of your existing account and on the new one or use a second browser to be logged in on both at the same time.
Go to the settings, create your profile and change the password!
If you find this post useful, please resteem it.
There may be others who fail to register.
And of course I am also happy about a comment or vote.