Hi @Hash and welcome to the RStudio Community 
Quick tip, whenever you ask a coding question on here, it helps people reading it (your potential helpers) if you can also include your data (or any data that has the features of your original data... in case you can't share it). I highly suggest you take a look at this awesome article: FAQ: How to do a minimal reproducible example ( reprex ) for beginners
Having said that, the difference-in-differences (DID) in R is actually fairly simple to implement. It requires just a bit of manipulation of your data and the standard lm() function. I could have provided help if you had shared a sample dataset 