Hi and welcome to the Community,
First thing to mention here is for
There are only friendly voices here. Doesn’t mean nobody will ever challenge you over time and will only scratch your back 
but it means that empathy, constructive comments and overall ‘sharing our passion’ with respect is deeply embeded in the philosophy of BJS and the members of this Community.
Feel free to come here anytime with your questions, showcase your progress and make us wonder about the amazing results you achieved. Also feel free to challenge the framework where you think it could be improved and don’t hesitate to report any bugs (that will be swiftly taken care of 
)
As for your project, you could start by having a look at this tutorial. Sadly, the site is no longer active but there might be some information left in the tutorial that could help you (about recording the state of objects and things).
I’m not a specialist of this but I would say record a before and after state (and as shown in the tutorial an active state). On first click on the piece, activate the before state instructing that after can come next. Then after clicking on a valid square to move the piece, run the animation while setting the active state and on animation end (or move end) run the after. Something like this. Again, there are people in this forum that are much more knowledgeable than me on this. I hope some will spot your question and feed you with their experience and expertise. Meanwhile, again, welcome to BJS and have a great day 