Overriding changes?

Hi,

I have just started using Sell Media and it’s great however i am having some problems with all the updates.

I like to make small changes to the layout in the php and also add a few extra classes and things like that (because this is how my customer would like it to look) but every time there is an update, it all gets overwritten.

Is there any way of allowing small changes without losing everything when updating?

Thank you

https://ww.wp.xz.cn/plugins/sell-media/