Help install No Longer Evil on 1st Gen Nest

I am struggling to do this, and I can only find videos on gen 2, not 1. I removed the silver panel, but here are 2 issues I'm facing.

- I can't seem to remove the battery. NLE instruction says to lift it up, but it doesn't come off that way. The connector looks like a slide connector, but it doesn't slide out either. How do I disconnect the battery cable?

- The panel is so tiny that it's hard to see which parts to connect using a tweezer like the instruction says.

If you own Gen 1 and have done this, please share tips. Thank you.