Click on the iMove icon on your dock.
Choose Create Project.
Save
Go to File/Import and browse photos and movies. (whatever folder you want to choose your imports from)
After importing the movies drag them to the StoryBoard at the bottom of the screen in the order you want.
To add an opening Title click on Titles and type the words you want in the spaces above the word Titles. Make sure Over Black is selected.
Select the kind of animation you want for your title by click on one of the blue animations (3-D Spin, etc.). You can change the speed, size, and font.
To add a subtitle to a slide, uncheck Over Black, type the words, select the time you want the subtitle to show. Then select the photo you want the subtitle on and drag the animation to that photo.
For transitions, place the arrow on your timeline between two items, click on Trans and choose the blue transition animation, and drag the speed button to make the transition last a shorter or longer time. Then drag the animation to the intersection of the two items
You can try different video effects also by selecting Effects then selecting one of the effects previewing it and then selecting apply to add it.