FIND
Specify fields that will be retrieved via query. Check SOSL API - SELECT.
Fields
You are able to add a default fields to selector class. More fields can be added in a place of usage.
SELECT Id, Name, BillingCity, BillingState, BillingStreet
FROM Account
public inherited sharing class SOQL_Account extends SOSL implements SOSL.Selector {
    public static SOQL_Account query() {
        return new SOQL_Account();
    }
    private SOQL_Account() {
        super(Account.SObjectType);
        with(Account.Id, Account.Name);
    }
}
public with sharing class MyController {
    public static List<Account> getAccounts() {
        return SOQL_Account.query()
            .with(Account.BillingCity, Account.BillingState, Account.BillingStreet)
            .toList();
    }
}
Parent Fields
Specify relationship name and pass parent object fields.
SELECT Id, Name, CreatedBy.Id, CreatedBy.Name
FROM Account
public inherited sharing class SOQL_Account extends SOSL implements SOSL.Selector {
    public static SOQL_Account query() {
        return new SOQL_Account();
    }
    private SOQL_Account() {
        super(Account.SObjectType);
        with(Account.Id, Account.Name);
    }
}
public with sharing class MyController {
    public static List<Account> getAccountsWithCreatedBy() {
        return SOQL_Account.query()
            .with('CreatedBy', User.Id, User.Name)
            .toList();
    }
}
Count
SELECT COUNT() FROM Account
SELECT COUNT(Name) names FROM Account
public inherited sharing class SOQL_Account extends SOSL implements SOSL.Selector {
    public static SOQL_Account query() {
        return new SOQL_Account();
    }
    private SOQL_Account() {
        super(Account.SObjectType);
    }
}
public with sharing class MyController {
    public static Integer getAccountAmount() {
        return SOQL_Account.query().count().toInteger();
    }
    public static Integer getUniqueAccountNameAmount() {
        return SOQL_Account.query().count(Account.Name, 'names').toAggregated()[0].names;
    }
}