There are essentially two options for getting gas.
One option is unattended or automatic gas stations. For those you need a true chip and pin card. Most American cards are chip and signature and won't work when the station is unattended. A handful of true chip and pin cards are available to Americans. I got one from Andrews Air Force Base Credit Union and it worked for gas in France. Andrews is a horrible financial institution, however, so I wouldn't recommend them - and I'm not sure it's worth the effort to add a gas option.
The second option is attended gas stations. You can use any form of payment including cash or credit card (chip and signature is fine). Gas at toll road rest stops are always attended. I use them as a last resort because they are considerably more expensive than regular gas stations. The best option I found was asking at my lodging where an attended gas station could be found? Many big grocery stores have gas; they are attended some hours and automatic outside those hours. Other bigger gas stations with attached convenience stores are similar, they're attended many hours and automatic outside those hours.
When a station is attended put in gas, then go in to pay. That seems to be the norm in Europe. I had similar in Ireland and Northern Ireland in May. Apparently people won't drive off (or the penalty is stiff enough to deter it).