next and prev arrows

[Veda273]

I am thinking to enhance the user experience on the "How to Join BioTree" section. I think it would be a nice improvement if the steps appeared one by one, allowing users to navigate through each step by clicking a "Next" arrow. This could help guide users through the process in a more interactive way. Additionally, a "Previous" arrow could be added for easy navigation back to previous steps too.

@subhadipbhowmik iam willing to work on this issue, please assign this to me under gssoc extend'24