Creating a table space sql developer
Since you quoted SQL Developer in your question -

View > DBA

Add your connection.

Go to Storage, Tablespaces.

Right-click, 'Create New'

Fill in the details - and I agree with Gerard Pile's comment to your question - you don't need to worry about what you're worrying about. Just pick a directory, file name, and intial file size, and how you want it to grow, with an optional max file size.



You could theoretically override the database's DB_BLOCK_SIZE on the 'Properties' page, but that's generally not necessary.

If you want to see the SQL that's generated by the dialog, click on the 'DDL' page of the popup, otherwise, just click 'Ok.'