sfdx force:source:push command can be used to push source to Salesforce Scratch Org.
1. Create a Scratch Org. If you are newbie, please check the following link to create a Salesforce Scratch Org.
2. Use the following command to push the Metadata to the Scratch Org.
sfdx force:source:push --targetusername [email protected]
Here, [email protected] is the username of newly created scratch org.