Micro models allow training quickly on a small data set in minimal time. The technique is simply training on the new data with no preservation. If you add too much data or train for too long you will damage the model notably, but it is an easy and quick way to get one character into a model.
Unzip the file into your /training_samples folder. It will create a subfolder on its own to work with the trainer.
On the command line, use v1-finetune_micro.yaml which is setup for this case. You may wish to slightly change the REPEATS for your data set, with 31 images and repeasts 50 the output is fairly good and completes in just 13 minutes on an RTX 3090: