Guide very clear and toolset and replacement battery worked just fine. I replaced battery without disconnecting front panel. Both glued strips got broken (I didn’t remove Taptic Engine) but I managed to rescue strips by carefully leveling up battery with the spudger and picking the strips with twezzer. Then it was easy to pull the glued strips thanks to the gap gained between battery and rear panel
Iphone 6s is back to life. Sorry for my poor English writing skills (creo que escribo mejor en Spanish)
Thank you all