I find pretrained model for Swahili ASR on huggingface and it works good https://huggingface.co/Akashpb13/Swahili_xlsr
Code to generate submission you can find here https://colab.research.google.com/drive/1VuVD9HCIlpTHEAbSqnAB-N2BVyivlS2_?usp=sharing