Is there any way to change the setting in Multiplayer quick game so as to make sure your opponents are of a similar level than yours?
I am a newbie and have a level of 15. My opponents are always level 50+
I found it really hard to learn as i normally find myself defeated after just a few turns

Levels don't necessarily imply more skill, just more experience. If you want to learn more about the game, there are lots of ways to do so. You can try applying to clans that focus on strategy, read some strategy guides, analyze other people's games, join discord servers and much more.

Here are a few links to get started:

Warzone public discord: https://discord.gg/Ur63KEVtEa
Strategy guides: https://www.warzone.com/Forum/168132-strat-guides
Ladders: https://www.warzone.com/Ladders

Thanks for your reply.
I am going to have to rephrase my question: Is there any way to adjust the setting so that when clicking the "Play now" button, you end up playing with someone of similar skills/experience/level or whatever tp yours?

I appreciate ther tips you gave me on learning but it would be nice to be able to put into practice in games that last more than 3 turns

You can play ladders once you level up (which will pair you with opponents of similar skill after a series of provisional games) or simply make an open game. There is no way to guarantee this in QM, though it will try to match you with an opponent that has a similar template/global rating.

Congrats Alexander on moving up to level 39 (as of the date of this post). I'm sure you realize that levels give no tangible benefits, only that the player has won enough games/earned achievements, About half my experience to be my current level came from completing single player challenge levels.

While a level 58 can seem daunting (it was the first time when I was level 18), after enough games you will realize its not a big deal (losing can teach you alot if you review the game afterwards).