i really want tomake a hybrid between a marigold and something else.
Ahem, grafting has nothing to do with making a hybrid plant. Hybrid plants are made by having sex. The plants have to be close enough to be able to cross breed. This is true of animals also. If they are compatible, you can make hybrids pretty easily (pluots, tangerines, roses), if they are less compatible sometimes it can be forced but the offspring may be sterile (can't make new copies of themselves), and then you can not hybridized non-compatible species: zucchini + corn = zucorn NOT, elephants + kangaroos = eleroos or kangaphants NOT, belugas (whales) + hogs = blogs!! Ok, that's an exception to the rule!
Depends what you mean by hybrid plant. Like if you want a tree that grows lemons and limes. Then you have to graft a lime branch onto a lemon tree and vice versa.
But if you want to grow a plant that bears a cross between 2 fruit then its more complicated. You have to figure out if the 2 species are closely related so they can cross pollinate and produce fruit. Then you would plant the seeds to see if it grows and to see if the fruit is the outcome of what your expected. Sorry for such the long answer :D