how do I install adobe flash player on my samsung galaxy tablet

You don't. There is no more Flash Player for Android and there won't be another. Android is no longer compatible with Flash Player. Playing Flash content is very processor consumptive and it drains your battery, also shortening the life of it. Android (Google) recommends using either "Dolphin" or "Puffin" as your browser if you need to view Flash content with a mobile device running Android. They're both free in the GooglePlay store. These browsers use "server side" rendering to reduce the load on your device.