@Youssef Benallai I don't know how thing are ran in your country for Real Estate Investments (REI) but I can give you an idea what REI is here in the U.S. so you can see some categories in RE, there are more but this is what I am familiar with and how a lot of young future REI's start off:
With the investments below you will want /need to buy distressed or outdated properties so you can create equity (money) by fixing/ remodeling in some cases you get equity instantly but in others it's long term just depending where you are investing, always do your research before you invest you want to make sure its an area that has potential growth in the near future or is growing now or the area has a high demand, so always do your research (hint I've noticed that where ever a Walmart is it tends to make the town or city grow) but that's just what I think and by my experiences here in Arizona, someone might tell you other wise but that's ok they are sharing their knowledge ;)
1) House Hacking: you buy a duplex or 4 plex and live in one unit and rent out the other ones, so your tenants pay the mortgage for you.
2) Live in Flipper: you buy a SF (single family) home again distressed or outdated you live in it for at least 2 years (to avoid capital gain) mean while you are fixing it nicely so when you are ready to sell the home it has gone up in value and you get equity (money) back.
3) Whole seller: You find home owners that have a distressed property or just can't keep up with the property or can't make payments on mortgage for what ever reason just a situation that they no longer want it. So I have heard a few different ways but here is what I understand from what I have read here on BP but do your research on all these that I have mentioned.
* you find the property you negotiate a price point that can be a win win for you and the owner, you put as little as $500 to hold the property than you find a REI that will buy it so they can make some money off the property and you put anywhere from $1000 - $30,000 in your pocket just for finding the deal.
You get the money and don't spend it you invest it again and again making your money grow. There is a lot more to all this so read, read, ask and due.
Like I tell my daughter "the ignorant one is the one that doesn't ask" ")
But again do your research, we are "Live in Flippers" (for now) so House Hacking and whole selling is something we have not done.
Once your get your foot in the door and get the experience than you can look at:
Fix and Flip: you buy distressed property fix it and sell it in as little as 3 months
New construction: you by the land and build a house on it and sell it
So these are some ways you can start in REI but first save as much money as you can :)
I hope this info helps you.and hopefully other BP members can give you more ideas and info ;D
Wishing you success. :)