Litematica is a modern Minecraft Java schematic mod. Using the fabric loader. You can use this mod on vanilla or fabric servers. You can download litematic or schematic files and import them into your minecraft world. In creative mode you can actually paste a structure or in survival mode it makes builds far simpler than following a tutorial.
You'll need to install fabric and then litematica (as well as malilib) the easiest way to learn how to install fabric and mods is to watch my tutorial video.
I've done a full length tutorial on using litematica, it's split into chapters since it's a pretty big topic.