How can I start writing a Warhammer Fantasy crossover fanfic?

Traveling through the Xianxia world, Chen Chen obtained the strongest tracking system and was able to track everything ever since. Chen Chen says, "System, I am short of money." "Two meters away, your father has hidden some money under the bed. Five meters away, there is a rusty copper coin buried half a meter underground." "There is a nugget of silver in the grass ahead." Chen Chen says, "System, I need some luck." "The feces in front of the pigsty is not ordinary." "Go to the Black Peak cliff ten kilometers away and jump off it." "There is an Immortal Cave Abode hidden somewhere, please explore it on your own."

[Alternative tittle: I Can Duplicate Everything] One day, a friend asked him, "Brother Qin, why aren't you cultivating?" Qin Yi smiled gently and said nothing. Cultivating? Why should I cultivate when I can extract Cultivation Points from you? With Cultivation Points, I can upgrade my cultivation base at any time. Not only Cultivating Points, but I can also extract your Spiritual Mind, Body Essence, Artifacts, Pills, Bloodline, Special Physique, and others. So, tell me, why should I cultivate?

A chance to change, challenge destiny, make dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish! In the modern world, a young man gains an unconventional system that gives him the power to transform into a fish! With this strange power, he shoots for the stars!

Qin Lin was playing a nostalgic game called “Ranches Story” when he was electrocuted. He suddenly discovered that he had the ability to enter into the game. He could even bring a watermelon he had planted in the game back to reality. At first, his plan was to sell watermelon for 2 yuan a catty. In that case, he could earn 20,000 yuan by planting 10,000 catties worth of watermelon in the game every day and selling them in reality. Later on, he discovered that by leveling up his ranch, he could obtain high quality crops that surpassed that of the real world. If he reared livestock, they were of far higher quality than that of reality. After he built factories, he obtained various recipes that far surpassed that of the real world. Everything changed after that.

A detective rolls up to a crime scene. Unknown to everyone else, he's the one who killed the victim in this case. And unknown to this detective, he's about to wake up in the Marvel Universe with an insane Warhammer System. How will he survive in a world where Thanos is guarenteed to succeed once? He'll do whatever he wants in this world while picking up some women along the way.

Zhou Yun transmigrated to a fantasy world and was bound to the God Tier Epiphany System. He could enter into a state of meditation and achieve epiphanies that others desired regardless of what he did. Other cultivators immersed themselves fully in hardcore training in order to achieve some improvements in their swordsmanship. On the other hand, Zhou Yun achieved enlightenment in swordsmanship by merely picking up a sword and playing with it a little. His swordsmanship attained perfection in an instant. Other cultivators trained hard in order to break through to the next plane. Zhou Yun merely swept a glance at the fallen leaves in the courtyard. Then, he had an epiphany and broke through to the next plane on the spot. He had insights into everything in the world, and his rate of plane progression skyrocketed. When other cultivators finally became powerful existences after going through various hardships, Zhou Yun had already become the supreme existence through having countless epiphanies.