You can start with our reference design by using a standard nRF52840 DK. Here you can find a DevZone blog, nRF Desktop on a Development Kit, with a step by step guide on how to transform the nRF52840 DK into a mouse, keyboard or dongle.
If you need help at any point, get in contact with our DevZone team.
To get your hands on this reference design kit (Laptop Mouse, Keyboard, Gaming Mouse, and Dongle) you can talk to your local Nordic sales representative. Alternatively, use our contact form to get in touch.