Can't open downloaded workspace

Hello, ive recently downloaded MCreator so I'm totally new to it, I'm trying to create a mod and wanted to do a cave biome, so i downloaded a base mod that ive seen here: https://mcreator.net/forum/66175/how-make-cave-biomes-tutorial-kind?page=1

But my problem is that whenever I try to open it, i receive a message that says:

"This workspace uses unsupported generator type: forge-1.15.2

Select one of the supported generators for the workspace."

How can i solve this? Also sorry if it is a stupid question but i really know barely nothing of this software.