i want to be able to hear the first track at the same time

hi this is probably totally stupid, but… i can record a track through the mic and play it back, when i press record again it records the next track but i want to be able to hear the first track at the same time, but i cant hear it, ??? please help

You need to enable “play other tracks while recording new one”.
The option is in Preferences, but it’s in different places according to which version of Audacity you are using.