Hi @fazup welcome to the /e/ forum. This message on your device is rather misleading! as I noted in this article Know your hardware - Samsung - device is really saying “Ready” - it seems to now be fully ready for the “instruction” which you see on your PC “now do the reboot into new Recovery”!
However, if you are still waiting patiently, read the whole article, where I also describe the significant “First boot in TWRP”.
RECOVERY upload successful
Is telling you that Easy Installer has completed replacing the “Samsung/Android” Recovery with the Recovery chosen by Easy Installer - probably e-Recovery - this is the name of the /e/ custom Recovery, much like TWRP is a custom Recovery.
The “recovery” program was indeed uploaded to the smartphone successfully.
What was difficult at this step :
to act against what the message says “Do not turn off…”
I finally understood that the volume button can be pushed on the upper part or the lower part (unlike a keyboard’s key), I thought my phone was a model different from the one documented in the easy-installer instructions, with one volume button instead of two.
I have executed the more detailed button instructions from the “know your hardware - Samsung”, to reboot into “teamwin” sucessfully.