You can use two methods for OST to PST converter
With the help of OST to PST Converter tool
But, Manual Method is not applicable in all situations and it is a little bit complicated.
So, I recommend you MailsDaddy OST to the PST converter tool. With the help of this tool, you can convert ost to pst easily without any long method. If you want to test this tool you can search MailsDaddy OST to PST converter tool or visit MailsDaddy official website