Install Ubuntu and manual partitioning

[mahesh]

Hello!

I'm trying to fresh install Ubuntu 23.04 on a new disk.
Ideally I would like to use 4 partitions like I did last time, but it doesn't go well.
What I did until now is that I use 2 disks. One for the current one, and one for the previous version.
So what I would like to do is to install over the existing partitions of Ubuntu 21.

When I start and go to manual partitioning (Manual but using the GUI), I have:
sda1 vfat 976 MB
sda2 swap 31GB // I read somewhere I need twice the RAM amount. Not sure why it's 31, it should be 32 but it works.
sda3 ext4 / 122GB. Ubuntu 23,04
sda3 ext4 /home 1TB

So the idea would be to format only sda3.

The problem: The "next" button is grayed out, no way to proceed.

Any idea of the reason?

Next question:
I tried to restart and make a new partition table (without save and proceed).
When creating a new partition, I have only 4 options: Ext4, XFS, Btrfs and swap. How do I create an EFI partition?
In the past, I could choose "efi" for the first one, and it was pretty straight forward.
Once created, using "change" provides more configs, but not efi.

Thanks for your help.

Elodie