I'm getting errors from downloaded project and all project libraries are installed

I've downloaded a project that is running for my colleague but I'm getting errors in my Visual Code.

import { ApiModelPropertyOptional } from "@nestjs/swagger";

import { IsString, IsEmail, IsOptional } from "class-validator";

I've installed Nest.JS locally and I'm still getting the errors from the imports above saying cannot find module which appears throughout the project. There are errors with Share and copying the Shared folders seem to fix the issue but again if this is a snapshot of their project why are we having to do this?