How to Validate Your Model

We have the data and for example, OpenAI with Azure supports with pre-training. So we've trained it. So how do I know that my model is valid? We will split the data sets into training set and validation set. The training set consists of training and we will check the model with our validation set if accuracy is good. And what do you determine to be goes well? It passes 80%, 90%. so again, early on, I would imagine the number would be lower,. but over time, as you feed it more training data, the validation data is also going to be growing.