How to switch OSes?

System Details

  • Device: Grabbiter
  • OS: Ubuntu 26.04 LTS
  • Firmware Type: UEFI Full ROM
  • Firmware Version:
  • Internal storage type: emmc 32gb

Summary of the Issue

I recently managed to successfully install Ubuntu 26.04 LTS on my Dell Chromebook 3100 2-in-1, but I noticed it stuttered quit often and takes a while to open applications. I think it is a RAM issue(which I am not surprised, it is a 4 year old computer with 4 GB of RAM). I want to try and change my OS to something light like Lubuntu(will take any recommendations for other OSes) as this is mainly a browsing and youtube machine. The problem is that I don’t know how to get onto the UEFI interface and I am completely confused. This could just be something in the OS that I could change and if that is the case, I would like to know what to do. I am new to Linux and any help would be appreciated.

TL;DR: How do get back into the UEFI interface to change distros?

reboot and press ESC on startup when prompted