Hallo Hussain,
the SAP Learning Hub free edition contains a "NW001_Col10_EN_1.2" / "SAP Netweaver Overview" lesson, where you can check the basics of NetWeaver.
More details are here: http://scn.sap.com/docs/DOC-51591.
If you can use the "advanced" versions of the SAP Learning Hub, some lessons contain access to test systems too.
See more details here:
- https://training.sap.com/shop/learninghub
- https://sapecom-production21.tangentlabs.co.uk/asset-manager/cdn/static-pdf/LH-Registration-Guide-1.pdf/DE/EN
Also, there are some free demo / test versions of R/3, you can see the details here:
- http://scn.sap.com/community/downloads
- http://scn.sap.com/community/about/blog/2014/02/17/the-software-download-search-or-where-has-this-package-go
Best regards,
Laszlo