You have several options for getting energy early on. The easiest and fastest way is to build large solar panels. They are reliable, but only produce energy during the day. Also, you must build a Battery that stores excess energy and can give it away to energy-intensive buildings such as domes.
In addition to solar panels, you can create wind turbines and Stirling generators that can produce energy continuously, but have their own costs, advantages and disadvantages depending on location and terrain. It's up to you to decide which energy sources are best for your current situation and location.
All generators must be connected to buildings with cables. Fortunately, it's simple. All you have to do is select a cable from the build menu and simply drag it using the left mouse button from the power source to whatever building you want to use. Just make sure the building lights up yellow, indicating that it is connected correctly. Otherwise, you will build a cable that connects nothing.
