Goto the Company Apps, and click ADD APP
Select for SAML Test Connector (SP) (type saml in the search window)
Change the Name, eventually upload the logo
Now SAVEyou configuration
Add your SP Identity to the Audience e.g. https://<servername>
Add your SP Endpoint to the Recipient and ACS and Login URL Fields e.g. https://<servername>/plugins/servlet/saml/auth
Now configure which field you want to use as userid of the Atlassian App , e.g. username
Do not forget to save the setup
Download the SAML Metadata
Open this file and copy paste this in your Atlassian Application