To keep your audience from feeling overwhelmed, you should keep the text on each slide short and to the point.
Some experts suggest using the 5/5/5 rule: no more than five words per line of text, five lines of text per slide, or five text-heavy slides in a row.
PowerPoint Tips: Simple Rules for Better PowerPoint Presentations (gcfglobal.org)
15 PowerPoint Tips to Make Your Slides More Effective
How to Avoid Death by PowerPoint (David J Philips/TEDxStockholm)