You cannot create a database in rextester editor because you are already in the database. You can directly create tables...
--Sql Server 2014 Express Edition
--Batches are separated by 'go'
--select @@version as 'sql server version'
CREATE TABLE Persons (
PersonID int,
LastName varchar(255),
FirstName varchar(255),
Address varchar(255),
City varchar(255)
);
insert into Persons values (1, 'ln', 'fn', 'address', 'cty')
select * from Persons