You can download Veeam Backup & Replication (VBR) and the Windows and Linux Agents for free.

VBR isfree for 10 Instances (VMs or Server - or 3 Workstations for 1 Instance) forever - this is called community edition.

This is enough to play around with Veeam and get some experience with the product.

I would suggest that you look at the blog post from @haslund:

First of all, this community here is a very (very) good starting point! You can ask questions and post your own experiences if you want. If you completely new to Veeam software, you can start at the Veeam helpcenter: https://www.veeam.com/documentation-guides-datasheets.html.

Read here basics about

• components:
  https://helpcenter.veeam.com/docs/backup/vsphere/components.html?ver=110
• backup:
  https://helpcenter.veeam.com/docs/backup/vsphere/about_backup.html?ver=110
• recovery:
  https://helpcenter.veeam.com/docs/backup/vsphere/data_recovery.html?ver=110

Furthermore, you can (and should  ) join you local Veeam User Group:

https://community.veeam.com/groups