This fantasy novel series has more descriptions of the "other world" and the main characters than most novels of this genre. The thing is, this author, spends way too much time, on sum-zero dialogues (conversations that don't go anywhere), explanations that don't move the plot arcs or theme forwards, etc.
This first book, has a map of this "other world", but has no character summaries, or inside illustrations. The story (action) moves really slowly, the main characters spend a really short time span in this first book. I doubt that even a week goes by.
The main characters have real-life emotional and personal conflicts (denial in killing another sapient being, crisis in causing physical handicap of a family member, probably a sexual assault not emotionally treated, etc.) If this enriches the main characters in this fantasy novel series, the question becomes, do any of these conflicts, push the story forward??
The theme, apparently, is that four friends go to the Stonehenge ruins in England and get summoned to another world. Did the main characters want to be summoned? No. Did they have a real reason to go all the way to Stonehenge? No. Did the author explain why they went to Stonehenge? No. Can this be considered a plot hole? Yes! So, these four "friends" get summoned to another world (isekai-ed), to defeat a Dragoness. Do the main characters have martial arts training, magical training or special abilities? No, they are apparently regular people (fragile, weak and in total denial). This non-commited group of friends, aren't really convinced that they should, that they can, that they have no choice, but to defeat this powerful Dragoness. Even horse-back riding is hard for the main characters, not to mention, using swords, bows, armor, magic, healing spells, etc.
A group of abled/experienced elves and dwarves "train" and "teach" these "heroes" horse-back riding, martial arts and weapons training and magical skills (in the few hours before they traveled to the Dragon Gate).
So, what could be the point (that the author is trying to make) in choosing main characters that CLEARLY aren't capable, aren't convinced, aren't committed into being the "heroes" that this "other world" and "this story" obviously requires? This author over-explains and has excessive conversations of the main characters but never really explains or answers these questions... without coming out nonsensical, irrational or illogical. Can someone that worked as an "extra" in a Medieval Entertainment Park, have the capacity to become a "real-life-Dragon-Slaying-Hero"? Can a group of "extras" from a Medieval Entertainment Park be really and truly considered real-life-heroes?