I know I’m late to the party and nobody will probably read this but…
A computer is a machine that does exactly what it is told to do. Exactly as it is told to do it. The only problem is, we don’t speak it’s language. At least not fluently or efficiently enough to give it the high end instructions we need to produce cutting edge software. Computers talk in 0’s and 1’s. We don’t.
So, we got a translator (source code) the can take our human languages and convert it into computer language and vice-versa.
Source code is the translator that allows us to speak to computers must faster and more efficiently.
Unfortunately, the translator is not perfect and can sometimes lead to mistranslations which is where computer bugs come from but that’s for a different eli5.
Latest Answers