How to save ManyToMany relations in TypeORM?

I need to create relations ManyToMany with using third table. Below is my code:

Account.ts

    @OneToMany(() => WorkspaceAccount, workspaceAccount => workspaceAccount.accountId, {
        cascade: true,
    })
    workspaces: WorkspaceAccount[];

Workspace.ts

    @OneToMany(() => WorkspaceAccount, workspaceAccount => workspaceAccount.workspaceId, {
        onUpdate: 'CASCADE', onDelete: 'CASCADE'
    })
    members: WorkspaceAccount[];

WorkspaceAccount.ts

    @ManyToOne(() => Account, {
        nullable: false,
        onUpdate: 'CASCADE',
        onDelete: 'CASCADE',
        primary: true,
    })
    @JoinColumn({
        name: 'accountId',
    })
    accountId: Account;

    @ManyToOne(() => Workspace, {
        nullable: false,
        onUpdate: 'CASCADE',
        onDelete: 'CASCADE',
        primary: true,
    })
    @JoinColumn({
        name: 'workspaceId',
    })
    workspaceId: Workspace;

And now I have a question, how to save this relations, in this way, that when I create new Workspace then automatically will be created object in WorkspaceAccount table?

Thanks for any help