Why this is in Remington Firearms Category I don't know, this is the VERY little I know about high point and taking them apart. You lock the slide and it exposed a take down pin, yes a PIN for take down! This adds to the list of why a lot of people don't like them, they are however generally reliable, fairly accurate, have a good warranty. On the downsides once you have it in your hands it's obvious, big and ugly, also insanely a take down pin to dissassemble but for the typical on sale $99 bucks purchase price a lot are sold!
I welcome someone to edit this post but this is what happens when you ask a Remington guy a High Point question, this however should get you started. I suspect after the pin is out it'll be obvious I'm sure your just looking for the typical take down lever.
The Remington guy is right. I own a Hi Point and you lock the slide exposing the pin. Your weapon should have come with a tool to remove said pin... don't loss it or your gun is worthless although some would argue that it already is.
Everyone's right about the take down pin. You can replace it with a small screw if you don't like the design. That aside, losing the provided tool isn't really a problem. You just need a drift punch to knock out the roll pin.