TRIBAN RC120 road/tourism bike

Hi all, I currently own decathlons budget road bike the rc120 and have completed a few long trips on it but solely on the road. I'd like to get into more gravel riding this summer and plan on doing a few week or 2 week trips. As I understand, I'd probably need to do a few modifications to make it suitable for this as in, changing the tyres and such so was just wondering if anyone has any experience modifying this bike and what size of tyres you were able to put on and how successful it was?

Thanks