Yes you have to go into the Epic Browser, Make sure unreal is selected to the left and click library at the top (next to marketplace.) Scroll down beneath the MyProjects section and you will find your Vault.
Find the asset(s) you require and click add to project, then select the project you want them in!
Every tutorial should have a link with the extra assets it uses included, somewhere in the tutorial. Usually as a step towards the beginning. Which one is it you’re doing?
Duh i misread you mentioned tutorial and assumed you got something from the marketplace my bad. @Mind-Brain should be right , as long as the tutorial doesnt use paid assets which unfortunatley some do. But most usually link to them