The government student finance page offers a helpful overview of the process. https://www.gov.uk/get-undergraduate-student-loan
Applications for Student Finance should always go through the online portal where possible as it speeds the process up. https://www.gov.uk/apply-online-for-student-finance
Once you start the online application process, based on the answers you provide, the Student Finance system will either allow you to submit your application online, or, if you are not eligible to do so, it will direct you to the paper forms to download and print.
The main student finance application covers all funding, including the tuition fee loan, maintenance loan and the supplementary grants (Parents' Learning Allowance, Adult Dependents' Grant and Childcare Grant).
It is important that you fill out the complete application if you wish to apply for all of the different funding types available.