The Keymap view is your main view. If you want to change what any key does on your keyboard you make that change here.
First you will see your keyboard represented on screen. Off to the right you will see your layers from 0 to 8, below you will see 2 sets of keycodes the one to the left changes based on the tabs above that way you can select " normal / ansi" keys or more special keys like " Shifted " a selection of pre shifted keys eg: !. To the right you will see a static block of highly used keys you may want. These keys are available in other tabs just collected here for your convenance.
To map a key you can do it in 1 of 2 ways. You can drag it from below and drop it on the key you want to change, or you can click on the key you want to change and then click on the key you want to change it to below.