Place the new battery down in the place of the old one.

Plug in the power cable, I found that the easiest is to just push it in with my fingers. Make sure it is well connected and flat down on the board.

I am not sure how to make the new battery hold. If you have double-sided tape, it might just work here.

Otherwise the battery kind of fits in there snugly and doesn't move that much. You might get away with just leaving it like this.

What is certain is that the old glue doesn't work for the new battery, so you definitely will want something to hold it in place here.