Or you can use LiteTween addon.It would be much easier, quicker and cleaner.
But unfortunately Scirra is reluctant to adapt it to the new runtime, even though it is extremely useful.
Indeed that's why I was reluctant to say use rexrainbow MoveTo as it seems impossible to add on Construct 3.
Develop games in your browser. Powerful, performant & highly capable.
I'm on the train to London doing this on mobile and a few beers in so may be a bit rough. But it works.
T in the lerp is linear so start stop with constant speed but as it is using lerp you can drop in a smoother line formula for t to make it ease in and out.
drive.google.com/open
arrows or hold/double tap move left right