You can invest online directly through the mutual fund company (AMC) website. As a new investor, there is a one-time documentation, called KYC (know your customer), which you need to complete. If you have a PAN Card, an Aadhaar card and online-banking facility, then you can start mutual fund systematic investments online immediately after fulfilling the KYC formalities online.
The other way is to contact a mutual fund distributor. The distributor will help you with the entire procedure and this is convenient for a first-time investor.