Let’s start with software
There a few different options for software to use to create your poster.
PowerPoint is a popular and easy to use option. This guide from University of Sterling goes through all the basics you might need when creating your poster, step by step.
Adobe InDesign is a professional design software, which is more complex to use, but can be used to create high quality professional posters. This video walks you through the process for creating a research poster in InDesign.
Make sure you save your poster as a PDF to send it for printing, so that the formatting etc. won’t change when you print!