Isometric in 2018.3

I have no idea where the person in the tutorial got that tilemap package from and why I dont have it even though I have at least 2018.3.

And everytime I try to use my own tile, it doesnt fit properly in my grid nor is it isometric. Also when I do my own, after putting it in the window, it takes up the full screen.

 

@SuperCrow2

"the person in the tutorial got that tilemap package "

People here are not mind readers - what / whose tutorial?

"...why I dont have it even though I have at least 2018.3."

In this case, it is not actually because you didn't have the latest version or something - actually if you do have later version (2019.x) I think you'll have to download the 2D Tilemap package from package manager. But if you are in 2018.3 or 2018.4 you should still be able to open the Tile Palette from Window/2D/Tile Palette without installing any package. You question heading says you are using 2018.3 so I think you should have the tile map installed. See thread:
https://forum.unity.com/threads/cant-find-tile-pallete.778328/

"And everytime I try to use my own tile..."

This is perplexing - first you say you don't even have Tilemap package installed - but then you have trouble using it?

Can you elaborate in what step you are actually now? Have you already got the Tilemap working but have trouble using it?

 

Here's the tutorial I was talking about. its around 2:07 or 2:08. I have no idea where the person got the built-in tile map from:

I did make my own tile, but everytime I put it in the "window" "2D" then go to "title palette" in the small window box that comes up, it takes up thr whole screen.

 

is it a bug? Because I dont have that tilemap folder in mine, the one that the tutorial used.