Hello @cfmathis !
Depending on what type of bike you purchased, you’ll have one of two types of valves for your tube.
Most people are familiar with a Schrader valve. This is a shorter and thicker valve and common on many trail and/or mountain bikes and kids bikes.
If your valve is on the longer and thinner side, this is likely a Presta valve. You find this on many road bikes.
Many pumps can accommodate both, sometimes by unscrewing the nozzle and reversing a piece inside to accommodate the larger or smaller valve type.
Let me know which bike or valve you have and I can assist a bit more. Also, let me know what type of pump you are currently using.