System hardware for new system

I am looking to setup a Asterisk system at a remote site for a proof of concept for a larger project in the future.
What I am looking for is insight and experience for the following setup that would work best for ones that have setup a system before so I don’t learn trial by fire per say.

So the site will has only a need for 5 phones which the need new ones is why this came up.
I have computer here that I can put asterisk software on it.

Looking for information on using 2 pots lines that are currently going into to site.

So not much but looking for insights from others on what they have used for the pots lines to interface with the asterisk system.

Let me know if you have any questions etc.

Use Digium cards or external gateway. I use external gateways.