There are generally three softwares which are used for checking the plagiarism in academic writing.
How to use urkund?
Firstly you need to visit the official website and login with the valid username and password.
After successful login, click on the upload documents to upload the document and submit.
As you have upload the document, after a set of time, the similarity report will be viewed on the home page. On clicking the analysis of similarity report, you can exclude some of the sources (like your already published work etc.)
After analysis, you can download the report.