There are several dedicated BL manga websites. For example, Mangago and Kissmanga have a decent selection. But be careful as some of these sites might not be legal or safe.
Most of the time, mangas are read right to left. This is a distinctive feature of manga layout and it helps maintain the intended reading flow and visual storytelling. But it's always a good idea to check the specific instructions provided with a particular manga if you're unsure.
You just need to visit the website mangazuki.topp and look for the manga you want to read. Usually, there are clear instructions on how to access and start reading.
The novels and manga of the Heavenly Official Blessing had their own advantages, so it was up to one's personal interests and preferences to decide whether to follow the novel or the manga first.
If you like the style and storyline of the manga, you can follow the manga first. Blessing of the Sky Official's manga had an exquisite style and a fascinating storyline.
If you like the world view, character setting, and plot development in the novel, you can read the novel first. The Blessing of the Sky Official had a huge world view, and the character setting was also very rich. The plot development in the novel was also very exciting.
Whether it was a novel or a manga, the most important thing was to be able to enjoy the pleasure of reading or watching. He could decide which one to pursue first according to his own interests and preferences.