At the moment, take profit orders cannot be taken in partials for a single position.

We are working on adding this full functionality in our next build, but for the time being you can replicate partial take profit orders by:

Manually reducing your position size at the desired level(s) by clicking the small ‘x’ in the Positions tab next to your position. Ensure one-click trading is disabled.

Entering your trade using multiple positions and splitting up your take profit orders across those different positions.