In this video we look at finding templates on Overleaf (Overleaf.com) and we look briefly at some templates for conference posters.  This video doesn't go into details on modifying individual poster templates, instead you are encouraged to look at the templates on Overleaf and focus on understanding them and modifying them.  In the long run this strategy will serve you better than basic instructional videos.
The versions of the posters that I modified for this video can be found here:

• Three column poster using the Beamer class: https://www.overleaf.com/read/hdzfsqqvndgm 
• Three column poster built on TikZ: https://www.overleaf.com/read/hbvkxzbgrnjz
• Three column poster with the Better Poster class: https://www.overleaf.com/read/wpxmjvdkfpnc