The mod author needs to update his mod to 1.01, or you can do it yourself, but I don´t know exactly where to find it.

Hint: go top the mod folder find the .mod and txpe in under supported_version="1.0.1"
Open with editor, notepad++ etc.

Thing is I don`t even know how to upload content from workshop to the game, so if someone could explain that I would be greatful ;)

Just hit the big "Subscribe" green button.

but it does not appear in MOD section when I start stellaris, so I guess I have to do something extra for it to be available...

It's supposed to be automatic: once you subscribe, the mod is downloaded and installed. If you don't have it, it's most likely a bug.

cheers, thanks for info

Once you click on the "Subscribe" button, you should get a message notice: "This item has been added to your Subscriptions. Some games will require you to relaunch them before the item will be downloaded."; if not, then something is amiss... but I haven't a clue what that might be.

Once that is done: click "Play" from your library, select "Mods" above the Stellaris "Play" button - there should be three tabs: News, DLC, Mods - select your mod and "Play"; away you go. I haven't a clue if you can select more than one mod... I only have the one... interesting question though.

Thanks for full explanation how it functions, I thought I have to download and make some manual file movement to get those in game ;)