Quite often a new ISP will need some specialist help to set up and configure some hardware and/or software. Usually this is to do with something that is a one-off requirement, although ongoing technical support will be essential if your are to keep up with the latest releases of essential ISP software.
There are also continual software updates for many standard internet software packages, often these correct discovered errors and problems as well as addressing security and privacy issues. Being aware of these updates and applying them will need an intimate knowledge of the particular software and often will require the ability to compile programs for your computer/operating system.

This is where many startup ISPs realise they need to become as self sufficient as possible for as many general system administration tasks as possible. Either get some volunteer, friend or associate who is already fairly clued-up with as many of the software systems you will need for your ISP operation or get into self learning mode as quickly as possible.
Fortunately there seems to be no shortage of volunteers and helpers who are more than willing to get involved in ISP technical support issues for no more than free access to the system and its internet connection.
Probably one of the most influential factors in such support has been the widespread adoption of the Linux operating system by ISPs. Every day there are growing numbers of people getting into Linux and where this is used by the ISP there is often a local pool of knowledge and one or more people with Unix (Linux) technical expertise.

Some of the real specialist tasks such as setup and programming of the router that will interface your network to your service provider's network is where you need to get your provider's technical people involved. An alternative here could be the people you purchase your routing equipment from. Make sure that one or the other will take responsibilty to commission and make operational your internet link