These resources are for general guidance only. For specific requirements like font size, orientation and poster size you must follow the requirements you have been given by your lecturer - if you are not sure check the module handbook or on GCU Learn.
Chapter: Conference Presentations and Posters pp 497-521
Chapter: How to Prepare a Poster pp 381-388
Chapter: How to Make a Good Poster Presentation pp 219-225
International journal of qualitative methods, 2019, Vol.18
You may also want to check out Sage Research Methods - a package to support all aspects of research. There are lots of ways to create your poster - we have linked to PowerPoint guidance and Canva below - as always check the requirements you have been given.