OK I’ve edited the question now… I found an answer to how using the splines but to complete the river I still need a flowing water material/asset, that’ll actually look like it’s flowing. I already know how to shape the river to the way I want it to using the splines but I still need an actual river. Anyone knows somewhere I can get a FREE flowing water material/flowing river asset?
Thanks and have a good day! 
Edit: The guys at discord helped me out and gave me an old live training video… But still I am curious if there is any FREE flowing water material, or a tutorial on how to make it. Like, a good tutorial, like the training live streams because these are great 
You could try digging out a trench using the landscaping tool then put a second water landscape under your normal landscape
Sorry. I found an answer to this question already in an old live training. But I still have a problem. I need to find a river material/asset. Using the splines to shape it the way I want is already solved but I still need something that actually looks like a flowing river… Ill edit the question right now
Instead of writing “I solved it” it would be nicer to add links or explain how you solved it for those who follow the question because they have the same problem
I kinda said how I solved it. I searched in Google for help, and found a VERY old live training video for splines. So anyway, I have created a spline that has a river mesh applied to it, with a construction script that will help me with custumizablity. You can find this if you search the live trainings. But just so you know, the video uses a different set of meshes, and you will need to think about the variables because of that… Sorry that I am not impleemnting a link. You see, im not home most of the time… I might implement it today when I come back home… Sorry again. Have a good day!
yes please link?