An "overview presentation" means to give a brief and simplified explanation or summary of a topic or subject. It provides a general understanding without going into too much detail. Full definition
The planning team created overview presentations on these topics and decided who would speak on each subject. (edutopia.org)
We too had used the tool to create our Corporate overview presentation. (elearningindustry.com)
National overview presentations on topics including: home visiting, early childhood mental health, child care quality, and program governance and systems. (zerotothree.org)